Combustion of fuel is usually hidden from sight inside that big hunk of metal called an engine. But Huib Vissier saw something beautiful in this process, so he built a simple engine that showcases combustion rather than concealing it.
Enter the two-stroke 1C, an engine that's so well crafted and polished it looks deserving of a spot in a museum. A glass cylinder contains the engine's white-gas fuel, pushing a graphite piston to drive the fly wheel. A magnet triggers the spark plug to start the ignition. If you'd like to get right to it, jump to to 1:35 to see the thing in action.
The device is not for sale (did anyone really expect it to be?) but if you're interested in building your own, here are some instructions to get you started. Learn more about how two-stroke engines work here. [Hackaday]