What a fantastic kata! Very original. Lots of kata enjoyment in this one. I suggest just having fun with it and letting your code flow naturally rather than going for the shorter code. Only criticism is the description should have stated there would be width and height parameters. Reading that description I wasn't sure what was going on there.

Ah, okay. Fair enough, I guess ;D

Yes, it was on purpose. I know that most grid structures are zero-based. My insperation for this came from a system that was not zero-based, so I decided to keep it that way.

Dude... It's super annoying, the grid not being zero-based. Most grid structures are. Was this on purpose?

I looked through the Codewars Wiki, but I can't find anything regarding what the requirements are to pass the beta process for a kata. Does anyone know the process for how a kata completes the beta process?

On this page (https://en.wikipedia.org/wiki/Cartesian_coordinate_system), it is pretty clear that it is (x, y). Throughout this entire kata I believe I was very clear that it is (x, y). I was very consistent throughout. Is this still an issue?

When writing this I was thinking about the mathematical side of things

That's exactly opposite of mathematical notation...

Random tests look good. Deinitely sufficient.

Your coding style isn't mine :P , but it works. ( Mine isn't the coding style to end all coding styles either. )

Well, it's even called getXYPosition, not getYXPosition. Charlie, between FArekkusu and me, you can be at most 50% off base. No reason to change.

I'd like to get on with my life now.

As long as they're collapsed, it's not a problem. 400 uncollapsed still produces a noticeable hiccup. Fortunately, if you collapse headers, it remembers that.

100 random tests may make more sense than 400 predictable ones though.

Sorry, this is my first kata. Just added some random tests. Let me know your thoughts on them and if you think they suffice.

You are speaking about function plotting, but I'm speaking of matrices.

And it's also specified poorly. When I made a kata dealing with matrices I wrote a long message what (x, y) means, which of these refers to rows and which to columns. Here we've got a long boring example which some users may skip only to find out that the author mentioned somewhere that he's living in some alternative dimension where

[
  [a11, a12, a13, ..., a1N]
  [a21, a22, a23, ..., a2N]
  [a31, a32, a33, ..., a3N]
  [..., ..., ..., ..., ...]
  [aM1, aM2, aM3, ..., aMN]
]

coordinate of a23 is (3, 2)...

I've seen other kata use (x,y) instead of (y,x). Yes, it's baffling, No, I wouldn't do it myself, but hey - it's legal.

Mathematically, aren't x and y ( and then z ) often used in just that order? How is it wrong?

As long as it's specified, how can it be wrong?

OK, now you need random tests. You ( practically ) always need random tests. You should have had random tests from the beginning. Never ever again publish a kata without random tests. :]

Because people will hardcode test results. Also, which is a much better reason, random tests may find edge cases nobody ( including you ) had thought of. When one is found, ** add it as a fixed test ** ( if only because CodeWars will revalidate existing solutions based on fixed tests only ).

Not having random tests from the beginning often means people will downvote your kata regardless of anything else ( I will ). And they may not come back to change their vote, even if you add random tests later. You're not doing your kata a favour by publishing it without random tests.