This idea is for manufacturers of USB cables and the devices they plug into. You may not be aware, but we users of your products inevitably try to plug the cable in upside down each time we fumble around with it. This annoys us. But there is an easy solution!
Put a dot on one side of the cable plug, and a dot on the corresponding side of the receptacle. Problem solved. See below.
There’s another free idea beneath this flower: