All I remember is sliding down a waterslide made of wood, but where the water is just running down some planks, where you sit astraddle... you'd think it would be splintery, but it isn't, it's very highly polished.

(I was at the beach that day, and a girl was concerned about sitting on a log, because of splinters, which did not seem to me to be much of a problem, being that it was soft driftwood)