Pedro FloresPeople in the United States started playing with the British bandalore or yoyo in the 1860s. It was not until the 1920s that Americans first heard the word yoyo. Pedro Flores, a Philippine immigrant, began manufacturing a toy labeled with that name. Flores became the first person to mass-produce toy yoyos, at his small toy factory located in California.
Duncan saw the Flores toy, liked it, bought the rights from Flores in 1929, and then trademarked the name Yo-Yo. Duncan's first contribution to yoyo technology was the slip string, consisting of a sliding loop around the axle instead of a knot. With this revolutionary improvement, the yoyo could do a trick called "sleep" for the first time.
In 1920, the first true hair dryer came on the market, but it was extremely large and heavy, and frequently overheated. Since then, thousands of patents have been issued for different hair dryer designs, but most of them only tweak the outside packaging of the hairdryer so that it looks more aesthetically appealing to you. Aside from the addition of some safety features, the inside of a hair dryer hasn't changed too much over the years. Not until 1951 was the first really workable dryer made. The device consisted of a hand-held dryer connected to a pink plastic bonnet fitted over the woman’s head.