Crab computing: building a biological machine

The buzz around cloud computing is oh so 2011! That’s because the latest and greatest in terms of computational advancements (or should we say "sidesteps") is a sort of biological concept "computer" based on swarms of soldier crabs.

Japanese researchers from Kobe University came up with the creepy, crawly concept after reading research from the 1980s which posited that one could theoretically build a computer using the movement of billiard balls—with a bit of Newtonian physics and an idealized, friction-free environment thrown in.

That research, by Edward Fredkin and Tommaso Toffoli, used the billiard balls’ motion as a substitute for electronic signals, with researchers looking at how the balls collided into one another or emerged from a series of gates in a predictable direction and at a certain speed.

In layman’s terms, the researchers were trying to show the behavior one would expect from a logical gate (AND, OR, NOT), by using physical principles.

In an electronic circuit, the logic is "enforced" by using electricity, i.e.—either there is an electric current or there isn't at one of the inputs of the logical gate.

The researchers wanted to see whether they could use simple physical processes (the bouncing around of billiard balls in some environment) as a way of applying the same logical gates in an electronic circuit.
The problem they discovered, however, is that this is energy inefficient, because of all the power lost making the gates work.

As a result, Fredkin and Toffoli used simple physical processes (the bouncing around of billiard balls in some environment) as a way of applying the same logical gates in an electronic circuit.


If one were to imagine a pool table, with all sorts of small walls arranged on it, sort of like a maze, with many entrances and exits, that arrangement would represent the "hardware" of the computer. The logical gates.

The "software" is represented by the billiard balls, placed at some of the entrances, and then rolled into the maze with some velocity.

The combination of which entrances the billiard balls are put into, and the arrangement of the walls on the table determines which ball rolls out at which exit from the maze.

And presto: you have the makings of a computer.

What’s extra cool about the whole thing is that it’s also reversible, so if one were to roll the balls that came out of the maze back into the exits they came out from at the same speed they exited, the exact same inputs would be achieved.

There is very little energy lost in such an idealized process, which  is a big deal, if one were to consider all the coal operated power plants it takes for Amazon, Facebook, Google and the likes to maintain electricity to keep their datacenters going.