The Three-Wheeled Skateboard
I saw one of these in the flesh recently, being hawked by one of the Chinese factory suppliers at the ISPO.
In fact, he had several versions of a similar board on his stand, which he proceeded to demonstrate for us. All of them had that kind of shopping trolley-wheel at the front, and all of them required a tic-tac movement to get them going.
What’s wrong with a conventional push you ask? Well quite.