As a novice draughtsman, I used to use a Stanley knife for cutting things, one day I forgot to retract the blade and leant over something, as I returned to my seat, the knife - BOUNCED - on my right leg, thought nothing of it for a minute and the looked for the knife on the floor, as I bent down I saw a small cut in my jeans (lax office dress code), there was a small 10-15mm cut, I sneaked off to the toilets and found I had cut into my leg, it was a perfect triangle and had only gone through the dermis, but you could just see the muscle below - very lucky, I had the foresight to take the masking tape off the desk and basically bandaged it, went to the medical centre on site and they plastered it. A few days later while having it looked at - it had fluid under the skin, as I moved it around it opened the would and it jetted out like a leaky hose pipe, just missing the head of the nurse who was just going to have a look - she jumped back very quickly.