I made some changes to my monster picture according to comments in the critique. I wasn't able to change it as much as I wanted before the monster show, but this is what I was able to do in the time I had:
My next project is pretty complicated but I've been making slow and steady progress. (Speaking of slow and steady...)
Here were my first few steps.... first, the original Escher image which I was inspired by. Next, I experimented with many different shapes and positions of a tortoise and a hare to find one that would work. I brought this sketch into the computer in order to regularize the shapes.
Next, I figured out what I wanted the "finished" tortoise and hare to look like, then I put those shapes together in the tile pattern I wanted in the final. Then I found what the central tile/tesselation would have to look like and put that together in the same shape.