Creeping damp

When I was at Primary school, we used to play football. Or at least a variation on football. Leather footballs didn't last very long when used on a concrete playground. Plus they had some serious concussive properties when belted against the heads of younger pupils. So a new rule was introduced. Sponge footballs only. Or Spongies as we called them.

Our playground was a square concrete box. It didn't take long for the surface of the ball to lose its coating. Then you were playing football with a sponge. In Scotland. The ball would land in a puddle and immediately sook up all the water. If you kicked it, you got soaked. If you headed it, you were showered in dirty puddle water. Eventually big bits of sponge would start to come off the thing, and you would end up playing with a considerably less than spherical ball. Anything more than 50% mass was considered still playable.