The old rubber toys I remembered where very hard rubber, I guess they needed to be to hold up to kids like me and my brother. very cool. clay marbles are one of the simplest forms of child entertainment from the past that manage to survive as evidence that kids played. no telling how many very "serious" games were played with that marble, there always seemed to be a marble shark that dominated an area. As a kid, you strived hard to be one yourself, there was nothing worse than losing all your marbles to someone.