To be able to design any manufacturable item, you have to know that a wrench is used to tighten bolts, and a screwdriver must be able to reach the screw. There

To be able to design any manufacturable item, you have to know that a wrench is used to tighten bolts, and a screwdriver must be able to reach the screw. There are people who don't. Some of them graduated engineering school with me.