Why do animal-hairs grow into a nice even coat? Daedalus reckons that they are controlled by infrared light signals propagating to the follicle from the hair tip. Cutting one's hair spoils this system by creating flat ends that reflect the light. But with a fluorescent hair-spray that absorbs visible light and re-emits infrared, the natural regulation mechanism will be reestablished, and no-one will ever need a haircut again.