The evolution of the motorcycle caught on with other inventors, when a German engineer named Gottlieb Daimler worked for another engineer named Nicolaus Otto. Nicolaus Otto decided to build a "four-stroke combustible engine," in 1876. This in turn gave Gottlieb Daimler an idea to take what Sylvester Roper had already built, but make it even better, so he decided to use Nicolaus Otto's combustible engine and attached it to a bike that he made out of wood. The difference with this invention is that Daimler built this bike to run on gas instead of coal. This in turn became the true adaptation of the motorcycle, even though it was actually more of a bicycle. The better term would be a motor bicycle. The wonderful thing about creative ideas, is that it usually comes from someone else. Most people feel that they can do even better than the original creators ideas, so it was no surprise when William Harley and two others named Walter and Arthur Davidson, who were both brothers, decided to take the motorcycle idea even further in 1903.