It uses piezo actuators as the "legs", operating them at different phases to move in different directions. This was explained on the YC submission a few days a

It uses piezo actuators as the "legs", operating them at different phases to move in different directions. This was explained on the YC submission a few days ago: http://www.hizook.com/blog/2009/08/29/i-swarm-micro-robots-realized-impressive-full-system-integration http://www.hizook.com/blog/2009/08/29/i-swarm-micro-robots-r... http://news.ycombinator.com/item?id=795396 http://news.ycombinator.com/item?id=795396