can happen if you are getting careless.
As I was today. Wanted to Chrony my rooftop slingshot, and focussed too much on not hitting the equipment... so I hit my hand instead. With a 1" steel ball. The same that goes through 40mm particle boards.
It got deflected, and still hit the catch box with enough force to topple it over. But it also wounded my hand, very significantly. Here you see my "flight path" to the bathroom, to pour some water over the hand.
My wife says I need stitches. I don't think so, it is just a deep nasty cut. But I better listen - this time.