This robot doesn't need any electronics
https://www.sciencedaily.com/releases/2021/02/210217151054.htm
The team, led by Michael T. Tolley, a professor of mechanical engineering at the Jacobs School of Engineering at UC San Diego, details its findings in the Feb. 17, 2021 issue of the journal Science Robotics.
"This work represents a fundamental yet significant step towards fully-autonomous, electronics-free walking robots," said Dylan Drotman, a Ph.D. student in Tolley's research group and the paper's first author.