Chris Fenton has released the files allowing you to build your own 3D printable mechanical computer.
This is is a simple, 3D-printable (caveat: It requires some springs, bearings, rubber bands, and nuts/bolts), fully-mechanical computer. It has 3, single-digit base-10 counters for memory, and processes a chain of 10-position punch cards. With the included program, it will compute the first few digits of the Fibonacci sequence.
You can find project details on Chris Fenton’s website.