A-man says it's based on the Farnsworth-Munsell Hue Test. A cheat-proof test designed to pick up variants on red-green colorblindness. The granddaddy version, a Munsell Color Tree, is now on my "overpriced toys that I might buy if I can talk myself into it" list.
I have completely neglected lj since going into bead-overdrive. I swear I have lots to say, it's just that I MAKE BEADS. I'm almost at 25 finished pieces. When I get there, life will slow down (probably).