ttile
Wow, don't the fish interlock nicely. In it Eschers brilliance shines through. He painstakingly experimented with shapes that have this interlocking properties, without losing the animal in the process.
We can appreciate his hard work by puzzling ourselves. Which primitives recreate the ttile?
Implementation
With some effort the ttile can be defined succinctly. Quickly, use it in
geometry
binary.