Hopscotch, roller skates, skipping, five stones and jacks, the big ship sails through the alley, alley-oo (however that's spelt) – that required lots of us, so not every day – made-up games of being grown-ups (about 17 but incredibly independent and wealthy), dens made from a blanket and the clothes horse (indoors) or the frame of the garden swing (outdoors). My friends and I also invented a game we played on the way home from school whereby you had to have your feet off ground whenever a car went past you, then we made it more difficult by insisting that you couldn't have your feet off ground in the same way for two or three cars running – so if you sat on the pavement for the first one, you had to kneel on the wall for the next and do a handstand for the third. We were always late getting home and had incredibly dirty and hands clothes from grovelling around on pavements. How many games did individual children invent that depended entirely on having a wall, a stream, a fence, a hard surface, a patch of grass, whatever, in particular places in relation to each other, so that balls and bats behaved in a specific way and a mind-boggling scoring system could be in place?