A friend of mine wanted to make some speaker-stands from some thick pieces of wood, in a Z shape. He didn't know what angle to cut it, so asked me (knowing tha

A friend of mine wanted to make some speaker-stands from some thick pieces of wood, in a Z shape. He didn't know what angle to cut it, so asked me (knowing that I had, some years earlier, obtained a maths A-level). The problem reduced to solving a quadratic, but I couldn't remember the formula for the solutions (-b ± something?) so spent 2-3 days trying to reconstruct the proof (this was pre-internet). Eventually I cracked it, and enjoyed the process so much that I applied to study maths at University ... He never did make those bloody speaker-stands.