I agree … and if I ever had the choice … I’d go with Robertson or Torx for all my screws

But we were talking about (I thought that is what we were talking about) is what common basic screw design would be common to appear in a world where no screws existed. A slot is simple and easy to make … just take a metal saw and cut one slot and voila you can turn it with a simple flat screwdriver head … simple to make, simple to reproduce … a pain in ass? yes? a universal torture device that will make your life miserable? yes?

But if we ever end up in a situation where we have no hardware stores, no manufactured supplies, no heavy machinery, no metal stamping equipment, no heavy duty presses then cutting a simple slot across the top of a threaded rod is the easiest way to make your own screwhead and start working with using your own homemade screw driver … a pain in the ass? yes … but at least you can screw things together after the world has ended.