I like how this chart shows a pattern between the prime numbers and their final digits. However, it doesn't seem practical to recreate this chart on a test any time you want to check whether a number is prime.
Mark Erickson. I think this is the architect in me, but I really really LOVE the detail of this piece. The watercolored water and terrain is so organic. The white masked hexagon pattern underlay has been so carefully executed, it really creates a third dymanic to the piece. The thin, crisp black ink outline distinguishes that map. This is awesome!