The chained letters puzzle

I just invented a type of puzzle that I call “chained letters”.

The purpose of the puzzle is to decode a number sequence in order to find the underlying word.

Let me explain.

First of all, this puzzle is meant to be case insensitive.

We begin with the most obvious correspondence: the 26 letters of the alphabet and the numbers from 01 to 26. So, the letter A corresponds to the number 01, the letter B corresponds to the number 02, and so on up until the letter Z which corresponds to the number 26.

Now we choose a word, whatever word we want. It would be best if it is a word with many letters. Why this is so, will become apparent later.

Then we substitute each letter of the original word with its corresponding number.

If we stop here, then it would be the easiest task in the world to decode the word from the number sequence.

But we do not.

What we do next is to change each number, advancing its value in a cyclical way. The change is as much as the value of the previous number in the sequence. And the first letter of the word, well, we change that according to the value of the last number.  This is depicted in the following image.

What does advancing in a cyclical way means? It means that if we have the number 24, then advancing it by 01 will give us the number 25. Advancing it by 02 will give us the number 26. Advancing it by 03 will give us the number 01. Advancing it by 4 will give us the number 02. And so on. We go from 01 up to 26 and then we wrap back and continue from 01 onwards again.

Let me give you an example.

First of all, it will help if I write down the correspondence between letters and numbers.

01 A
02 B
03 C
04 D
05 E
06 F
07 G
08 H
09 I
10 J
11 K
12 L
13 M
14 N
15 O
16 P
17 Q
18 R
19 S
20 T
21 U
22 V
23 W
24 X
25 Y
26 Z

Suppose we want to code the word “JUSTICE”.

We begin with the letter sequence:

J U S T I C E

Then we create the initial number sequence:

10 21 19 20 09 03 05

This is easy to do.  The letter J corresponds to 10, the letter U corresponds to 21, and so on.

Now we begin the difficult part. We will change the value of each number according to the number that precedes it. And for the first number, we will change its value according to the last number.

Let’s begin.

It is important to keep the initial number sequence intact and create a new one to be the result of our operations.

So let us begin by changing the second number.

The second number is 21. The number that precedes it is 10. So we will advance 21 by 10. Normally, this would give us 31. But we will not perform a regular addition. We will perform a circular addition where we wrap at 26. Thus 21 will become 05. So we will substitute 21 with 05.

The third number is 19. The number that precedes it is 21. So we will advance 19 by 21. Normally, this would give us 40. But since we are doing a circular advancement, 19 will become 14. So we will substitute 19 with 14.

The fourth number is 20. The number that precedes it is 19. So we will advance 20 by 19. Normally, this would give us 39. But since we are doing a circular advancement, 20 will become 13. So we will substitute 20 with 13.

The fifth number is 09. The number that precedes it is 20. So we will advance 09 by 20. Normally, this would give us 29. But since we are doing a circular advancement, 09 will become 03. So we will substitute 09 with 03.

The sixth number is 03. The number that precedes it is 09. So we will advance 03 by 09. Normally, this would give us 12. And since 12 is less than or equal to 26, we will accept this result as is. So we will substitute 03 with 12.

The seventh and final number is 05. The number that precedes it is 03. So we will advance 05 by 03. Normally, this would give us 08. And since 08 is less than or equal to 26, we will accept this result as is. So we will substitute 05 with 08.

Now let us change the first number. There is no number that precedes it, but we do everything circularly here, so we might as well continue in this path. We will use the value of the last number to advance the first number. So the first number is 10. And the last number is 05. So we will advance 10 by 05. Normally, this would give us 15. And since 15 is less than or equal to 26, we will accept this result as is. So we will substitute 10 with 15.

Please note that we could have done any of these operations in any order. We need to keep the initial number sequence intact. Then we can substitute each number with its advancement in any order. In the example above, I calculated the substitution of the first letter as the final operation, but I could have done it in the beginning or at any other time.

So let us see the final number sequence that we created:

15 05 14 13 03 12 08

Let us see the corresponding word:

O E N M C L H

So, if we give this word (that we calculated as our result) to someone, could they decode it? Could they derive the original word it came from, if the algorithm that we used is known to them?

It is important to keep the algorithm public and everyone should know the algorithm, meaning the procedure we used to derive the result word.

So, can someone derive the original word from the coded word? If someone knows our algorithm, and we give them the word OENMCLH, can they find out that the word it came from is JUSTICE?

Well, the result word does not resemble the original one, except for the fact that in this puzzle the initial word and the final word will always have the same number of letters. But even if the result word looks completely scrambled, we can reconstruct the original word it came from as follows:

We take the result word and we substitute the corresponding numbers.

So from

O E N M C L H

we come to

15 05 14 13 03 12 08

This is straightforward.

Next we can begin with any number and move in a cycle. So we might as well begin the first number.

The first number is 15. We know that we arrived at this number by augmenting the number that was there initially, using the last number in the sequence which is now 08. Yes, the last number is now 08, but we do not know what it was when we used it to augment the first number.

No number in this sequence is the original number that existed in the initial sequence. All numbers have been changed.

So what are we to do?

What we can do is suppose that the first number was originally 01. And see where this takes us.

Next we will suppose that the first number was originally 02. And see where this takes us.

And so on, until we check for all 26 possibilities for the first number.

Each time we suppose that the first number was something (from 01 to 26), we will come up with a number sequence. Then we will gather the 26 resulting number sequences and see which one corresponds to a valid word. The 25 other number sequences will be discarded. But it gets easier. Most, if not all, of the 25 number sequences, will not even be completed, since there will be an inconsistency when we wrap around the final to the first letter. So, most if not all of the 25 number sequences will be completely invalid. This is not because they will result in a meaningless bunch of letters, but because they will not result in a valid sequence that wraps validly around itself. This is because by supposing that the first letter was something, we will finally end up calculating the last letter, but when we derive this last letter, it should produce the assumption we made for the first letter. Usually, the only case that this will happen is when our original assumption for the first letter was correct.

Anyway, what we should do is assume each of the 26 possible numbers for the first number and calculate the original sequence that corresponds to this assumption. If we are able to finish the calculation and get a valid result, this is a strong hint that this result may correspond to the word we are looking for.

In the end, we will collect all the valid resulting sequences (theoretically their number will be from 1 to 16, but usually there will only be 1) and see to what words they correspond. The word we are looking for should be straightforward to find.

OK, let us see how we will proceed to find the original number sequence from the final number sequence

15 05 14 13 03 12 08

We will have to make 26 assumptions and then the calculations that correspond to each one of these assumptions.

So we will first assume that the original first number was 01.

So the corresponding calculated assumed original initial sequence is

01 …

If the original first number was 01 and now it is 15, this means that it was shifted by 14. So this means that the last letter was originally 14. We will keep that in mind. When we arrive at the end of our resulting original sequence and the last number is 14, this sequence will be a strong candidate for our final check. If not, this means that this sequence is definitely invalid, the assumption that the original first number was 01 is definitely invalid and we can safely discard this assumption and this resulting initial sequence.

By assuming that the first number was originally 01, we can deduce that the second letter was originally 04. This is because it is now 05 and its preceding letter was 01, so from 04 it was shifted to 05.

So the corresponding calculated assumed original initial sequence is

01 04 …

Now that we found the second number, we can find the third number. The third number is now 14, but since its preceding number was 04, then it means that it was originally 10 and it was shifted by 04 to become 14.

So the corresponding calculated assumed original initial sequence is

01 04 10 …

Now that we found the third number, we can find the fourth number. The fourth number is now 13, but since its preceding number was 10, then it means that it was originally 03 and it was shifted by 10 to become 13.

So the corresponding calculated assumed original initial sequence is

01 04 10 03 …

Now that we found the fourth number, we can find the fifth number. The fifth number is now 03, but since its preceding number was 03, then it means that it was originally 03 and it was shifted by 26 to become 03. In this circular addition, there is no zero as a number. We do not have any zeros.  But if we add 26 to a number, we get the original number.

So the corresponding calculated assumed original initial sequence is

01 04 10 03 26 …

Now that we found the fifth number, we can find the sixth number. The sixth number is now 12, but since its preceding number was 26, then it means that it was originally 12 and it was shifted by 26 to become 12. I repeat from the previous paragraph: In this circular addition, there is no zero as a number. We do not have any zeros.  But if we add 26 to a number, we get the original number.

So the corresponding calculated assumed original initial sequence is

01 04 10 03 26 12 …

Now that we found the sixth number, we can find the seventh number. The seventh number is now 08, but since its preceding number was 12, then it means that it was originally 22 and it was shifted by 12 to become 08. I repeat from the previous paragraph: In this circular addition, there is no zero as a number. We do not have any zeros.  But if we add 26 to a number, we get the original number.

So the corresponding calculated assumed original initial sequence is

01 04 10 03 26 12 22

We finished, but… we found that the last number of the original sequence is 22. And we assumed that the first number was 01. Thus, in the final sequence it would have been shifted by 22 to become 23. But in the final sequence we have at hand, the first number is 15. Thus we arrived at an invalid resulting initial sequence. Thus, we can safely assume that 01 was not the first letter of the original initial sequence.

We can then assume that the first number of the original initial sequence was 02 and do all the calculations. And so on. Each time, we will keep the resulting initial sequence if it is valid, I,e, if the last number calculated validates the assumption of the first letter. And we will see which of the valid resulting initial sequences correspond to a legitimate word. But, usually, there will only be one valid resulting initial sequence.

So let us do the calculations for the correct assumption, to see how this goes.

The initial word was

J U S T I C E

and  the initial number sequence was

10 21 19 20 09 03 05

But the solver does know that. All the solver knows is the final number sequence

15 05 14 13 03 12 08

Now let us suppose that the solver has tried all possible cases up from 01 up to 09 for the first number of the original sequence and now the solver is about to try the case for the first number of the original sequence being 10. We know that this is the correct assumption, but the solver does not. Let us see how this goes for the solver.

So the solver assumes that the original first number was 10.

So the corresponding calculated assumed original initial sequence is

10 …

The second number in the final sequence is 05. This means that the second number of the initial sequence was 21. This is because 10+21=05 in our circular addition.

So the corresponding calculated assumed original initial sequence is

10 21 …

The third number in the final sequence is 14. This means that the third number of the initial sequence was 19. This is because 21+19=14 in our circular addition.

So the corresponding calculated assumed original initial sequence is

10 21 19 …

The fourth number in the final sequence is 13. This means that the fourth number of the initial sequence was 20. This is because 19+20=13 in our circular addition.

So the corresponding calculated assumed original initial sequence is

10 21 19 20 …

The fifth number in the final sequence is 03. This means that the fifth number of the initial sequence was 09. This is because 20+09=03 in our circular addition.

So the corresponding calculated assumed original initial sequence is

10 21 19 20 09 …

The sixth number in the final sequence is 12. This means that the fifth number of the initial sequence was 03. This is because 09+03=12 in our circular addition.

So the corresponding calculated assumed original initial sequence is

10 21 19 20 09 03 …

The seventh number in the final sequence is 08. This means that the fifth number of the initial sequence was 05. This is because 03+05=08 in our circular addition.

So the corresponding calculated assumed original initial sequence is

10 21 19 20 09 03 05

And we finished. Now we must check the validity of the sequence. The last number produced is 05 and the first number is 10. Does 10+05 produce the first number of the final sequence? Yes, it does. 10+05=15, which is the first number of the final sequence.

Thus, the sequence we produced with the assumption that the first number is 10 is a strong valid candidate. And chances are slim to none that another valid sequence will emerge. But I suggest that the solver tries all 26 assumptions for the first letter of the initial sequence just in case.

So the corresponding calculated assumed original initial sequence is

10 21 19 20 09 03 05

And if we substitute the letters, we get the original initial word

J U S T I C E

Now this game can be played by choosing a word, encoding it using the circular algorithm I described and letting the solver deduce the way to decode the word. The solver should be able to deduce that she needs to try 26 possible assumptions for any letter position she chooses and move circularly calculating the resulting sequences. Of course, the solver can make the initial assumptions not for the first number but for any number in the sequence that she chooses. But there is no benefit or loss in what position she chooses to make the initial assumptions. But the solver has to deduce that she will have to make 26 assumptions and then perform the corresponding calculations for each assumption.

The word to be decoded should be long, in order to avoid letting the solver do the calculations by hand. This puzzle is meant to train aspiring cryptographers, so it would be best if it is designed such that it would persuade them to use a computer and create a program to do the calculations.

A student may create a program that decodes such a puzzle word and also a program that encodes (creates) such a puzzle word. And students can play against each other. One student can encode a word and the others could try and decode it.

Also, this puzzle can be made more difficult. For example, the symbols may be increased. As is, this puzzle deals with 26 symbols, the uppercase letters of the alphabet. Of course, a space, other symbols, the lowercase letters, numbers, etc. may be added. If we add, say, only a space, so the students can create an elementary sentence (just a space, no point, comma, etc) then the number symbols will be 27 and the addition will need to wrap at 27.

The difficulty of the puzzle can also be increased by circularly adding the previous, say, two letters to the current letter. And, in such a case, for the first letter, we would add the last and second before last letters. (Remember, we do things circularly here; not only the addition is circular, but also the way each letter is produced from the previous one – or more). So, if we choose to add the previous two letters to the current letter in order to shift it, we would have to make 26 *26 = 676 assumptions. So, to solve the puzzle we would need to calculate each assumption: each permutation of the first two letters, assuming we choose to work from the beginning of the number sequence. (Because, again, I am stressing that we can choose to begin to work from any number position in the sequence. And we can choose to proceed from left to right or from right to left.) Anyway, in such a case, we would assume that the first and second numbers in the initial sequence were 01 and 01. And we would find the third number, based on the third number of the final number sequence. And based on that, we would find the fourth number and so on until we calculated the whole sequence. And then we will try the assumption of the first number being 01 and the second number being 02. And so on, until we try all 676 assumptions.

So how may this puzzle appear? How can we pose the question to solve the puzzle? Here is an example:

A word is encoded using the following algorithm. Each letter corresponds to a 2-digit number. The letter A corresponds to 01, the letter B to 02, all the way to the letter Z which corresponds to 26. By substituting each letter with its corresponding 2-digit number, an initial number sequence is produced.

Then, this initial number sequence is transformed as follows to produce a final number sequence. We take each 2-digit number and we add the previous (position-wise) 2-digit number. The resulting 2-digit number will be used in its place in the resulting number sequence. As far as the first 2-digit number is concerned, we will add the last 2-digit number to it to produce the first 2-digit number of the resulting number sequence.  This concept is depicted in the accompanying image, where a six letter word is encoded.

In order for the resulting 2-digit number to always be from 01 to 26, we always perform a circular addition (instead of a normal one), where we wrap our results at 26. Thus, a few examples of this circular addition are 01+01=02, 01+25=26, 01+26=01, 10+22=06, 26+26=26, etc. So, 00 does not exist and adding with 26 equals the number that is added to 26.

Finally, in the resulting number sequence each 2-digit number is substituted with its corresponding letter. Given this resulting word, your task is to decode it, thus finding the original word.

So, given the following word, what was the original word that was used to produce it?

R  X  W  W  S  R  M  Y  Y  C  S

 

 

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Posted in Education

My attitude towards the flat Earth conspiracy theory

People who claim that the Earth is flat rather that spherical, and people that just are not sure whether Earth is flat or spherical, all they want is scientific proof in order to believe this or anything else for that matter.

And this is the mentality that science teaches us to have.

Richard Feynman said “Religion is a culture of faith. Science is a culture of doubt”. This means that in science, we welcome the doubters. Actually, we favor the doubters. Whenever something comes up from a person/scientist/whatever, the person invites universities, labs and everyone around the world to look into her findings and try to duplicate her experiment or validate her thinking to see if she was right. This is how science works.

So, if someone says to me that the Earth is flat or round, I should say, let me reproduce your claim. I should not say “all right”. I should say “fine, let me verify it.” This is how we teach Physics. We put students in the Lab. We do not say things to them and hope they remember them. We put them in the Lab. We give them microscopes, telescopes, timers, paper and blackboards to do calculations. All these in order for them to verify or dismiss theories.

So, if someone says to me the Earth is round and I take it for granted, then I am not a good scientist.

And if someone says to me the Earth is flat and I take it for granted, then I am not a good scientist.

Also, and this is very important, if someone says to me the Earth is flat and I laugh at her, then I am not a good scientist either. Good scientists do not mock others. Good scientists present their findings. Good scientists educate and inform others.

Mainstream scientists ask: “How can there be people who believe the Earth is flat after all the findings we present, like photo’s from outer space of the moon landing?”

Good question. I am not laughing at these mainstream scientists and I am not mocking them, even though I know the answer to their question.

The answer is that they have to be careful to understand what the flat-Earth-conspiracy-theorists are really saying.

What the flat-Earth-conspiracy-theorists are saying is: “Forget all the findings you presented. Forget them. I do not believe them. All these findings are conspiracy theories made exactly in order to fool us and to make us believe that the Earth is round.”

Mainstream scientists may ask: “Why would someone fabricate such a lie? Why would someone conspire to persuade others that the Earth is round?”

To the last question, the flat-Earth-conspiracy-theorists might provide very interesting and/or irrefutable answers, but our discussion is not about if and why they might be correct or incorrect in their suspicions.

Our discussion does not concern whether there is a conspiracy or not and why they would believe such a thing. Our discussion is not whether they are correct or incorrect that a conspiracy exists.

Our discussion has to do with what these people are saying. And these people are saying that the Earth is flat.

But mainstream scientists have to understand that the flat-Earth-conspiracy-theorists are basing their claim by disregarding all the facts that mainstream science presents as facts. And by doing this, they act as any real scientist would act.

So, I and anyone in the scientific community should welcome these people. Because they are not doing anything that science forbids us to do. Instead they are doing what science welcomes us to do: doubt.

So, these people doubt what we present as fact. And they say: “Forget about what they taught you. If you were to forget everything you were taught and start your reasoning from scratch, what would be your claims?”

So these people argue that if we observe and reason, we will come to the conclusion that the Earth is flat. But if we watch the news or get information from others, we will come to the conclusion that the Earth is round.

I know many of their arguments and observations and reasoning. And I know many of the arguments and observations and reasoning of mainstream science.

And I will tell you my opinion: the Earth is round, but it is extremely difficult, even for a Physicist, to prove it, when they are up against an informed and well educated flat-Earth-conspiracy-theory-supporter. (For example, one cannot say “here is photo from outer space”, because they will tell you that you did not personally take it, so it may as well be fabricated.)

Which makes these people worthy adversaries, people who deserve our respect and honor and whose claims are extremely difficult to falsify. But it can be done, flat-Earth-conspiracy-theory-supporters can be proven incorrect, and this is one of the reasons why we need to educate ourselves as much as possible in science.

In “The Art of War”, Sun Tzu writes about the mistake of underestimating your opponent.

I, for one, do not underestimate the flat-Earth-conspiracy-theory-supporters. Quite the opposite. But there are indeed some mainstream scientists that underestimate the flat-Earth-conspiracy-theory-supporters. I do not think highly of these mainstream scientists.

Posted in Science

Completely dynamic full screen overlay in JavaScript with div or canvas

In this blog post, I am going to show you how to create a full screen overlay.

Say you want to create a full screen popup when you click at a particular web page element, or at any other event you wish. And you wish for the popup to appear and to cover the browser’s full client area. And you also wish for the popup to disappear when you click anywhere on it.

Fear no more, your old pal Dimitrios (Actually, were we ever pals? Really, I mean, have I even met you?) is here to help you.

I will show you how to create a full screen overlay in JavaScript and I will give you the full html code for the whole html page. And I will show you how to do it by including support of the browser’s resize event. And I will show you how to do it using two methods.

The first method will be by dynamically creating a div. The second method will be by dynamically creating a canvas. The dynamic div or canvas will have some text and an image displayed on them, to enhancd the educational value of this post and to better showcase the value of these methods.

But which of these two methods should you use? Well, it depends. If you want to include html elements in the popup, then you should definitely use the dynamic div. This is because the hmtl canvas cannot display html elements. You have to draw everything yourself. You have to reinvent the wheel, so to speak. But if you do want to draw everything yourself, then you may use the dynamic canvas method.

Here are both methods, in all their glory, again, by your friend (Honestly, have we ever even just met?) Dimitrios:

Creation of a fully dynamic full screen overlay using an html div element

Creation of a fully dynamic full screen overlay using an html canvas element

Actually, when I began creating these methods, I would use a naive implementation where I did not account for the browser’s resize event. So I had all the code in one function. Thankfully, the implementations I gave above, account for the browser’s resize and scroll events.

I would also use an empty static element (div or canvas) with zero width. But the browsers would account for it ever so slighlty, even if it was empty and of zero length. This had as consequence that the underlying page would be slightly different when the popup disappeared than it was before its apperance. So, I decided to make everything completely dynamic. And, this way, I achieved perfect results.

Another point I would like to draw attention to is the use of  “return false;” in the click event in the undelying page. At first I did not include “return false;” and I could not get the popup to appear for more than what it seemed to me like a millisecond or so. Thus, without the “return false;” the popup would appear and disappear immediately. It would not stay at its place and it certainly would not wait for you to click in order for it to disappear. After a lot of thought, I realized that it was because I was directed to a new page (the same underlying page, that was actually reloaded) and to stop this from happening I had to include “return false;” to stop the redirection from happening. “return false;” lets us stay in the same page and it does not reload the page.

The last point I would like to make is for you to notice that I use canvas.width and canvas.height, whereas I use div.style.* and canvas.style.* for everything else, where “*” in this sentence means “any attribute”. But canvas.style.width and canvas.style.height are invalid ways to address these attributes (the width and the height of the canvas). At first, I made this mistake and, again, the canvas would disappear immediately. This time, it was not because the page was reloading, like it happened with the click event. This time, the script would encounter this error and would stop executing.

So, there you have it. I hope we are friends now!

Posted in Web design

About computer languages, IDEs, and human rights

I do not find tasteful or nice to have to use needy IDEs like Visual Studio. I like to use Notepad for programming.

Visual Studio is very demanding when it comes to resources like CPU, Memory, Hard Disk, Operating System version. You need to have the best and latest hardware and Windows version. I cannot keep up. I can never keep up. And even if I could, I feel that using such an IDE deprives me of functioning as a programmer. Whereas Notepad is the exact opposite.

I know it may sound crazy, but here is how I see it:

When AIDS first reared its ugly head, the news started advising everyone to use a condom during sex. All over the news and anyone you would talk to, would advise you to use a condom during sex. Of course, this is excellent advice that saves lifes.

At one point, CNN showed a discussion about this very matter. An expert was advising a group of men to use condoms during sex. At one point, one of the men said the following:

“We feel we are not functioning as men, if there is something in between.”

This is why I love CNN. They are the only ones that always show both sides of an argument. No one else had ever or ever again raised an argument against protection during sex.

Although I would urge everyone to use protection during sex, I will paraphrase the words of that man. And I will say:

I feel I am not functioning as a programmer if there is something (like an IDE) in between.

I want to have control over the code I write.

To me, my idea of programming is using Notepad.

To me, my idea of programming is to take a binary editor and construct the executable byte by byte.

Actually, I want to make choosing the programming language and the IDE one uses a human right.

Of course, a company would be correct to insist that all employees use a particular programming language and IDE or a particular set of them. But an individual should always have to right to resign because she feels she would like to use another programming language or IDE.

Again, the choice of programming language and way of programming should be a human right.

Posted in Development

Google doodle programming for kids solutions

Today (2017-12-04) Google published a doodle that has to do with programming for kids.

Although this is the way kids should learn how to program, the doodle is incredibly difficult and should address only seasoned programmers.

The way kids should learn how to program is exactly like that, though. You can create a floor with square tiles and stand in one. Then let the kids give you orders to guide you where they want you to go.

But Google should have never produced such a difficult puzzle meant for kids programming. This puzzle should have been addressed to adults.

Anyway, here are the questions:

Question 1:

Question 2:

Question 3:

Question 4:

Question 5:

Question 6:

And here are the answers:

Answer 1:

Answer 2:

Answer 3:

Answer 4:

Answer 5:

Answer 6:

Note:

By the way, the answer for question 5 can also be used to solve question 4.

Additional information:

Obviously, the goal is for the bunny to eat all the carrots.

The puzzle does not make it clear what considers as optimal solutions. From the image below, we can understand that optimal solutions are those which use the least amount of components. The number in each question denotes the minimum mumber of components needed to solve it.

All

Of course, since question number 4 can also be solved using the solution from question 5, one could argue that question 4 should have the number 6 (instead of 7) for denoting the components needed. But using the solution from question 5 to solve question 4 is far fetched, so I believe that denoting 7 as the compenent number for question 4 is better as it stands.

It is interesting to see what the optimal solution for question 6 is, if we consider as optimal solutions not those with the least number of components but those with the least number of bunny steps.
Then the answer to question 6 could be the following:
– – ) [ – ) – ( – ) – ]
where – means move one step, ) means turn clockwise, ( means turn counter-clockwise, and [ ] means repeat 4 times what is inside the square brackets. I depict this answer below, using two images, since it does not fit in one.

a.PNG

b.PNG

Final note:

Of course, the algorithms that the puzzle expects as optimal are unacceptable to me. If I would see someone creating these algorithms, I would tell them that they are far from safe.

You should be able to look at an algorithm and immediatelly deduce its validity, correctness, function, purpose, etc. You should be able to look at an algorithm and immediately understand what its results will be.

Programming is not about which programmer is more clever than the other. It is not an exercise in obfuscation. It is, or it should be, an exercise in clarity.

Posted in Development

What is Glitch.com?

Glitch.com is a website that features an online code editor with which you can create, host and deploy Node.js applications and static websites.

You write the code online and that’s it! The deployment is instantaneous!

And yes, you can also use Express (the famous Node.js web application framework).

In the free tier, your code is public, so you can use this tier for open source projects and as a learning tool.

With Glitch.com, you do not have to install Node.js on your computer to serve a Node.js application. You only need your web browser to go to Glitch.com, write code and view the results.

Glitch.com‘s landing page has a lot of great ideas and examples for Node.js applications you can create and host on Glitch.com.

Glitch.com pricing is at the following link: https://glitch.com/forplatforms/.

A great article that uses Glitch.com to host and run the article’s featured code is the following: How to set up a database if you’re a front-end developer.

Posted in Web design

About racism

People call me racist. That may or may not be beside the point of this blog post.

We, humans, are designed to be racist. I do not like this, though, and this is one of the reasons that made me reach the conclusion that the human kind should not exist anymore. I do not think racism, discrimination, differentiation are just or moral. I want all people to be equal. All people are different, but that should not stop them from being equal.

I find it absurd to judge someone based on their skin color, sexual orientation, beauty, health, age, and so on.

But, as I previously wrote, we are designed to be racist. That is how we evolve. Again, I do not like it. But our designer is to blame, not us. What a bad, unjust, racist creation did she make: us. Yes, we should vanish from the face of the Universe.

I walk on the street and I see cafés. This is what I ALWAYS observe concerning cafés: If a woman is young and/or beautiful, she will be a waitress. If she is old and/or ugly, she will be a cleaning lady. ALWAYS. Let me make a mental experiment: Suppose I go to a café owner and confront her about this discrimination. Do you know what she will say? Well, let me guess. She will probably say that if she did otherwise, hiring the beautiful as cleaning persons and the ugly as waitresses, customers would not prefer going to this café. She would lose customers and end up going out of business.

And I am the racist.

Our creator programmed us to seek our sexual partner, our spouse, our companion, our friends, based on discrimination. As far as our spouse is concerned, we are programmed to pick and choose. If not for that, the human race would degenerate, instead of evolve. We choose good looking sexual partners to produce healthy children. This is our genetic predisposition. This is how humanity is programmed. Actually, this is how all species are programmed. And this is how nature works. Survival of the fittest and all that. Totally immoral.

Change is the only constant, as a wise man once said. And I take it from there: Those who adapt, survive. Those who do not, perish.

And I am the racist.

Anyone who ever had a friend, a spouse, a sexual partner is a racist. If you are married or have fallen in love, you are being racist. Only monks cannot be considered to be racist. All others pick and choose, discriminating people based on their looks, height, age, wealth and so on, in order to mate with them.

And I am the racist.

Or not. The point of this blog post is to prove that all of us are racists. Except monks. And monks are the only humans I respect.

Posted in Science