Div2 is a neural network that acts as a divide-by-two circuit, or as a counter. Run the network and then start toggling the status of Digit 1. Each time one digit goes from on to off, then next digit switches state. This small network consists of two divide-by-two circuits. Together they can count in binary code from 0 to 7.
It takes two cycles for the counting operation to propagate through each stage. If anybody can design a faster or simpler system, I would be very impressed.