Did you know that a sphere is the strongest geometrical shape? I didn't, but I learned quickly during my sophomore year when I put a stainless steel ball in the hydraulic press in metal shop. It didn't dawn on me to stop when I had to add a "muscle bar" because I couldn't pump the handle any more... (heck, I was sure I was gonna squash the durned thing plum flat)
It ended in a loud "bang"! The steel ball was found a year later in the ceiling, across the shop. We could tell which direction the ball went by the gouges in the press (it blew out about a 1/2 inch deep gouge 180deg from where I was standing). We did get the ball down one day when the teacher wasn't looking, there wasn't any damage to it...
The "bang" brought my brain up to speed with what I was doing REALLY quick, albeit a bit late had disaster struck. Oh to be that stupid again...