This is a mobius strip of Level 1 or Super Mario Bros. The whole level is wrapped around itself in a single surface, and poor Mario begins and ends at the same spot every time :(

All the elements from the level are there: every mushroom, turtle, cloud and star. They are all carved out of the surface at different heights, which looks fantastic when you have a light coming from the side, and each block casts a shadow.

It's a great piece to have on your desk, or to hang from a string to let it spin around.

Interlocking gears in a steampunk theme. These standard sized gear dice will keep your game turning (figuratively speaking, they do not actually turn...)

With percentile die.

DIY instructions for plastics can be found here, along with pictures.