This was a playful attempt to build a computer based upon an on and off switch controlled by bacterial communication. The bacteria track along the threads (wires) and interact with each other to generate a visual output. The vertical threads contain a colourless genetically modified bacterium (the indicator) that is in effect a mute, but which will turn purple when other bacteria “talk” it. The horizontal threads contain a bacterium that is also colourless but can “talk” to the mute bacterium (the transmitter). The bacteria move up and down the threads and where they interact, and close to the nodes, the indicator bacterium produces a purple pigment as it receives signals from the transmitter. The “computer” as produced an output but what is its meaning?