What the hell is the deal with all kids, everywhere, regardless of their time and culture, playing some version of 'The Floor is Lava'?? Some kind of impromptu game suitable for any location or number of players in which certain areas of the ground (particularly patterned tile floors) are deemed 'safe' to walk on and others 'off-limits' or 'dangerous' (like being a bottomless pit or lava or something). I'm not an anthropologist or behavioural psychologist or anything but it seems like this 'game' and its 'rules' transcends culture and time. Probably because it requires no skill or talent, equipment, time constraints, baseline intelligence beyond being able to walk and jump, or even any successful verbal communication--all making it easy to play anywhere, at any time, incorporating any number of players, and even when you can't understand each other.
Maybe it's just one of those things that kids instinctively gravitate towards.