Two Bionic Blinkenlights (neuromorphic analog integrate-and-fire neurons) with light sensitive excitatory inputs.
Both neurons have light dependent resistors (LDRs) that sense the firing of the other neuron.
When the ambient light is turned off, the spiking rate of both neurons slows down, and the neurons fire synchronously, with a 2:1 frequency ratio.
Measurement done at Integrated Systems Neuroengineering lab, UCSD