Two obviously related diagrams from a “lightning talk” I gave in 2010 entitled “Self Defence for Nerds”, featuring genuinely practical things from the otherwise often mirky, bobbins-filled and preposterone-pumped world of self defence. Inspired by Richard Feynman’s anecdote of standing away from the wall when he thought he was about to be punched, these diagrams show why you don’t want to be against a wall, and especially the ground, if someone decides to hit you. The accompanying punchline (sorry) was, “Now you have two attackers: your original assailant, and Sir Isaac Newton”.