Not Quite Wrap-up: The Half-Making Of Mortin Myes' Second Cryptic Gallery
This is not a solution to the puzzle, but provides notes from its poser. This type of answer has been approved by the community.
Caution: This post may contain spoilers.
Inspiration
I was playing around with binary pixel effects (i.e. if a pixel is 'on', turn it into some sort of pattern, and if a pixel is 'off', turn it into another. The typical one used everywhere, is 'on' is a black square, and 'off' is a white square!) and came across something particularly interesting. Now, the effect that I came across is actually a bit more difficult to decipher than what exactly has been presented in this puzzle, so I won't elaborate on it too much unspoilered here, but suffice to say it was the inspiration for this puzzle :)
Evolution
Well, upon finding the aforementioned effect, my first instinct was not to make a puzzle, but instead an encryption method. With a few random thoughts, I was able to create (what is in my opinion) a very very very difficult to crack encryption method for any sort of information at all, turning any message, textual or pictorial, into a sequence of 0s, 1s, 2s, and 3s... but that's a story for another day.
Anyhow, the purpose of an encryption is to essentially be an impossible puzzle, and puzzling.se is not a place for impossible puzzles. So, I backtracked a bit, back to the initial pixel effect. I decided to add one more layer to the pictorial encryption, and had to pick what to encode. In the end, I decided on numbers - there's something special about pixel numbers that makes this puzzle just a little bit easier.
What I failed to realise at the time is that same something special about pixel numbers also means that half of the encryption gets lost! If anyone remembers being around in the Sphinx's Lair, I realised this a few minutes in and said 'This actually might not be as difficult as I thought...' Thankfully, the difficulty seemed to be enough to keep some puzzlers occupied for a while :)
Anyhow, what has been discovered in this thread - and all of what can be discovered from this particular puzzle - is not actually the entirety of my intended encryption method. It certainly works for four digit numbers, and it's a perfectly acceptable solution to this puzzle from Mortin...
But for the curious puzzler, I'll pose a secondary challenge:
What on earth is THIS supposed to be?!?!?!?!?
Mortin's second painting
Pictured above is Mortin's second painting. As you can see, topologically identical to his first. But this painting provides crucial information that will explain the mysterious challenge above.
The process of making a Mortin Maze
Alright, so this is where we get into TRUE spoiler territory. If you've not yet attempted the secondary challenge, I'd highly recommend spending at least a few minutes on that before you read the following spoilers!!!
It's a pixel image! Once you've made a pixel image (in this case 5039), just make a lot of empty space around it. (Hey hey, arbitrary information)
THIS is the pixel effect. Are things starting to make sense?
Experiment a bit with making small pixel images and applying this effect. Maybe this is even enough information to solve the mysterious second challenge!
Above is what you get when you apply the effect to '5039'. Doesn't quite look like the painting in my question, does it? Because the information in this image can actually be simplified.
(Exercise to reader: Prove that up to this step, any Mortin Maze can be coloured in two colours such that no adjacent areas are the same colour!)
Above is how to simplify the information, by colouring in!
And if you 'unthicken' each coloured in section, you end up with the painting in my original question :)
How to DECODE a Mortin Maze
So maybe you're dying to know what the mysterious second challenge is. Maybe you're happy enough that you solved my original question! But to see the full extent of Mortin's encryption system, feel free to read the spoilers below.
Our mysterious second challenge, unedited.
Our mysterious second challenge, thickened. I wonder what the colours I've put in mean?
Our mysterious second challenge, thickened, and with a focus on verticals and horizontal lines. You can probably see what this is going to be now!
The next step is the hardest, it's identifying the RESULTS of the pixel effect.
Identifying the pairs of parallel lines next to each other gives this.
So our original pixel image was in fact:
Wowee! That looks familiar. But hopefully these pictures make it clear that the Mortin Maze encryption system is in fact much more versatile than the example I chose to pose to puzzling.se makes it out to be!
Final Thoughts
In trying not to make the puzzle too hard, I actually lost a bit of my encryption system. Hopefully it was still fun and difficult enough nonetheless, and consider the full encryption system a bit of an interesting easter egg :)