A chain with moving parts printed as a single piece. In my ongoing quest to make a trilobite I decided to experiment with printing pieces inside other pieces. This is an OpenJSCAD project that you can modify on my website. I'd first recommend making a chain with 3 links and varying the size of the gap to get it printing right on your printer. Then modify the other settings and print a longer chain. Raft recommended but not necessary. DO NOT USE SUPPORTS. If you print with supports the links will make a clicking noise.
Feel free to play with the parameters and then stop by the lab and I'll print you one.
Machine: FDM 3D Printer