George Sicherman sends me some really interesting designs. This one is along the lines of Stewart Coffins "Unhappy Childhood". The 12 checkered pentominoes can be arranged into the three shapes shown. Three wood species variations are being offered. All must have a checkered pattern as well. These were made with approx. .5" cubes. I spent some time with this and was only able to make the single layered solution. Then again, I'm not that bright!