Here's my attempt to do a tessellation piece inspired by Escher's work - the regular division of the plane. First up are some ugly block question marks, before I decided to bound the shape within a 3x3 box.
The idea of overlapping question marks hit me as I was sleepily sketching things through.
After figuring out the individual units, the struggle was whether or not to put the pieces immediately opposed to each other, or to give them a little space to breathe.
I decided that question marks are too awkward to be close to each other, and need a little space. They're introverts you know. They also LOVE math, like a younger me. Until I studied abstract algebra and realized there's a point where math loses function.
Final product, in a mockup frame. Galaxy watercolor scheme tossed in for good measure.