The students have been building a lot with paper straws over the last few months. The art of and engineering of Theo Jansen has been inspirational. One of our goals now is to build an open source $5 walking robot we can share with other school that do not have 3D printers and laser cutters. In order to hit that number the cost of the mechanical parts must be almost nothing. Paper straws and 4mm nylon screws meet that need.
The video is of one of the robot legs that costs $0.17 on a durability testing rig in the lab.