I recently visited a rummage sale at my local community college, which was trying to get rid of a ton of old and outdated equipment in storage to make way for a new Makerspace. As I browsed through the piles of nearly antique lab equipment, I stumbled across a small but valuable looking chest with a 4-digit combination lock. There was a piece of paper taped to the top, but it mostly looked like a random jumble of colored squares.
When I asked one of volunteers about, they replied:
Oh, that looks like Professor Margotof's old chest. He just left it here when he retired, and we've never been able to get a hold of him since. We think that paper used to have a hint to opening it, but some of his pet critters got a hold of it and messed it up. It's a shame, really. He used to keep some of his research results in there. No telling what sort of history that box holds!
My curiosity piqued, I ask about the "critters".
The critters? Those were a pet project of the Professor's, if you'll pardon the pun. It's hard to describe what exactly they were, because they didn't really have any intelligence, but if you got enough of them together they behaved like they did. He had three different types, and while they all behaved the same, they never interacted with any critters of another type, sometimes even passing right through each other.
I decided that this puzzle needed solving, so I bought the chest and brought it home. Here's a high quality reproduction of the paper that was on the chest:
And here's a smaller version, where each square is one pixel.
Can you unscramble the clue and find the code? Good luck!