New Scientist blogs about the ultimate Rube Goldberg cybernetic machine – a computer that uses living crabs for processors:
Yukio-Pegio Gunji of Kobe University in Japan and colleagues realised that when two swarms of crabs collide, they merge and continue in a direction that is the sum of their velocities. This behaviour means the researchers could adapt a previous model of unconventional computing, based on colliding billiard balls, to work with swarms of crabs, with 0s and 1s represented by the absence or presence of a swarm.
They then tried the logic gates for real, using swarms of 40 crabs. The crab swarms were placed at the entrances of the logic gates and encouraged to move by a looming shadow that fooled them into thinking a predatory bird was overhead. The results closely matched the simulation, suggesting that crab-powered computers could indeed be possible.