One of the most basic elements of computing is the logic gate, and researchers at Kobe University have turned to the animal kingdom to create a physical model of them — using soldier crabs. The researchers noticed a particular characteristic of the flocking behavior of the crabs: when two groups collide, they unite into one larger group whose velocity matched that of the two separate groups combined. This led the researchers to adapt a different physical computing model that uses billiard balls — with the balls taking the place of the signal — for use with the creatures. After running a software model, the researchers than created the real thing with the crabs themselves, using a shadow simulating a bird of prey to direct their movement. The real-world test performed on par with the software model, working perfectly for OR gates, but performing less reliably when it came to AND gates. While the practical applications are unclear, it's a fascinating experiment on animal behavior, and a testament to the flexibility of the basic circuits the form the basis of everyday electronics.