During the catapult project after my partner had to go home I decided to is my power drill to make some necessary holes in the wood that formed the base. So I went about it and I felt like I forgot something but shrugged it off. I learned about five seconds later that what I forgot was the clamps for the wood. The wood spun around and hit me right in the Charlie horse, an area behind the thigh that if its hit buckles which normally makes people fall. Now had my leg not stopped it under a circumstance in which friction and cutting of electricity did not feature the wood a would have continued to spin. thankfully for me it is a factor so it did stop after I stopped holding the drill.