Whatever happened to the robot revolution where robots would be doing the work of humans everywhere?

The problem, says integrative biologist Robert Full, is that “in the previous century, human technologies tended to be large, flat, stiff, metallic structures with right angles that used rolling devices and had few sensors and actuators.” Why not look to nature’s incredible design features to build robots that can cover difficult terrain, like cockroaches, or climb up smooth, vertical surfaces, like geckos? Why nature?