by loughkb, published
I used to make these out of wood. After cutting the shape, you would soak one end in boiling water until the wood was saturated. At that point, you could put that end in a vise and compress the finger down enough to reach the inner fingers. Let it dry, drill a hole through and insert a nail into the hole. Re-boil the end and the wood magically resumes its original shape, trapping the nail where it couldn't possibly be put.
The object should be 7cm deep by 9cm long and 2cm tall. Find or cut a nail to about 46mm.
The idea here, would be to pause the printer when it's about 60% up the hole, set a nail into the holes, and resume the print. You end up with a nail trapped in the object. The impossible nail.
At this date, I'm waiting for my Prusa kit to arrive, and building a few stl files ahead of time. If someone prints this, send me a photo of your trapped nail!