There were complicated rules about which way up the cards needed to land, or what happened if your card overlapped the white border of another card but didn’t overlap the substantive pattern.
But I digress. What I really wanted to mention was one time when I happened to see a couple of girls playing on the grass part of their playground, which was just over the fence from us. I don’t know what the game was, but every so often one of the girls would spank the other. It was only a gentle smack, but the rule seemed to be that one girl would kneel on the grass and the other would lift up her dress and pull her knickers up so that the smack landed on a partially bared buttock. I imagine this was what happened at home when the girls were naughty.