Tessellations were made famous by M. C. Escher in his iconic engravings. I worship those drawings, and have tried my hand at a few of them. They're an awesome intersection of math and art-- coming up with them takes lots of trial and error and redrawing and erasing. Changing the curve of one facet means that another curve on another of the pieces will change as well, so getting to a point where you have two things that fit together nicely and actually resemble actual objects (or in this case, people), is pretty time-consuming. Perfect for long plane rides.
Hope you enjoy this one-- drag the red ball to different locations along the bar to change the view of the tessellation in this interlocking chase scene.
Also, check out some of Escher's stuff when you get a chance. It's mind-blowing.