tangible toybrain

A while ago I made a little flash application I called toybrain that lets you create simple little networks of neurons that work like mcculloch-pitts neurons. They fire discretely (they're either on or off), they have and integer threshold you can set, they can have any number of excitatory and inhibitory axons. I made some examples with it, including logic functions, a temporal multiplier, a flip-flop memory, and a lateral inhibition network. Here's a screenshot (this is the flip-flop- triggering the leftmost neuron toggles the one on the right; the three in a triangle on the bottom store the state by firing in a loop):

So how about a tangible version of this? The individual neurons could make cool lights and sounds. The question is how to extend it beyond pure pattern play. Maybe you could build a little tangible neural net that controls a robot?