In the Forties (around 47), in Hollywood. A salesman from Duncan YoYo would meet kids outside of school (elementary) and walk us, in a group, a long block up to the corner drug store. He would then demonstrate all the tricks he could do on a YoYo. He was very good at it, and of course you could buy a Duncan YoYo at the Drug store. I was able to do several tricks but could never to “rock the cradle”