99 per cent invisible: 99 per cent details, Ep. 04

It’s a stick with bristles poking out of it. It doesn’t even qualify as a simple machine, but the careful thought and design that went into the creation of the modern, angled bristle, fat handled toothbrush shows just how much brainpower goes into something that is designed to simply work well and not be noticed all that much (until it’s time to buy the next one).