Few skateboards were created in the early 1970s, and those that were primarily came from toy firms. Technology was still in its infancy at the time. Decks composed of fiberglass and other polymers were almost as ubiquitous as solid wood planks. Plastic wheels were also new technology at this time. The first wave of modern skateboarding occurred in the late 1960s and early 1970s. The art form began with a group of artists and musicians in California who used skateboards as a means of expression. They staged elaborate stunts and performed music together which led to many innovative ideas for decks and wheels. Skateboard manufacturers took note and started making their own products. By the mid-1970s, almost every major company had released some type of skateboard product. In 1974, Tom Sims invented the half-pipe. It was originally called a "miniature mountain course" by Sims. He built it for his son to ride his homemade skateboard down. When Sims showed it to other skaters, they asked how much it cost and if they could have one too. So he sold them kits to build themselves. This invention sparked the need for more advanced tricks and maneuvers which led to many new products being developed over time. In 1978, Alan Gelfand invented the ollie--a necessary move for any good skateboarder today.