Bristlebots are about as simple as it gets, even in non-robot terms, they're simple. So, I thought, "Why not eliminate electricity and make a clockwork bristlebot?" Indeed! A tiny mechanical wonder!
Step 1: Bill of Materials
One clockwork motor sufficient to shake a small robot
Two brass wire brushes of your choosing
A small wood saw
A drill whose size of bit shall become clear in the following steps
Some kind of strong glue of your choosing