"And you can’t let it get cold, or it dies. But listen: if you want to reset it, you just flip up that patch in the back and expose it to sunlight. We put retinal cells there. When retinal cells see sunlight, they release glutamate. Which binds to receptors. Which produce nitric oxide. Which activates enzymes. Which add phosphate to a nuclear protein. The protein sends a genetic message, and the genes reset the neurons in the clock!"