The engine you see in the video above is a V8, and its made out of paper. The work of YouTubing engineer Aliaksei Zholner, the engine made entirely of paper with a few bits of scotch tape thrown in to help reduce friction.
According to Zholner, the engine is 32 mm long, 24 mm wide and about 27 mm tall. The shafts are 1mm in diameter, while the cylinder is 5.5mm in diameter, the piston stroke is 6mm long.
Zholner's paper V8 runs on compressed air and he's even made a throttle using paper, which really makes the little engine growl its anger out.