Pentominoes in a case

This is a set of Pentomino pieces in a handy carry case with swivel top. I designed it a few years ago after reading 'Chasing Vermeer' by Blue Balliett in which the main character solves a crime with the help of pentominoes. It's Nintendo DS size and a clear cover prevents the pieces from falling out. Later I made a batch of larger sets for our Maths department.

There are 2 layers of 3mm and 1 layer of 2mm acrylic. The surround of the Top layer was bonded to the Base layer with thin acrylic c