247 purpose of 156 reduction to the absurd 152 Stoic 150 Logic 150 logic gates 18, 22, 121 logic limit 262 London Bridge 42 London marathon 192, 202 London Mathematical Society 15, 238 London School of Economics 301 London Science Museum 16 long multiplication 240 Lorenz Attractor 173 Lorenz, Edward 170, 172 Lotus Corporation 2