alt Hacker News> The entire process is driven by instructions on a card drawn from a special deck created by the artist.
I like this. I like that his system pushes the creative process forward without relinquishing the actual creative part of it (making the map tile).
It's very similar to styles of generating lairs/dungeons in many TTRPGs. A lot of them come with various tables/dice rolls to help build a layout and then subsequent tables to give a general prompt for what goes in said rooms. It's an extremely satisfying routine, as you're not 100% beholden to every dice roll, but the dice rolls help prime the creative juices and give constructive constraints to the process.
I highly recommend trying it out for yourself!