I've made a laser cut version of the Goldfish - 3D Puzzle (http://www.thingiverse.com/thing:230128). The drawing is made in Inkscape. With the guide lines and extra green shapes it is easy to change the snapfit for the thickness of wood or acrylic you will use.
This drawing is made for 2.7mm of plywood.
fish_puzzle.svg | 107.4KB |