Alex took his original idea of the programmable LED and made it even cooler. He took 25 of his LED’s and put them together on 1 board. Each LED reacts to the others. Here is how Alex describes it:
The rule behind this is very simple. All fireflies have nearly the same frequency for their flashing, but their phase is shifted. If a firefly receives a flash of a neighbor firefly, it flashes slightly earlier.
Check out the Synchronizing fireflies
How to make a reprogrammable LED