Its four-stroke engine used a pair of side-by-side pistons to make 2 ½ hp, driving a bike that could achieve up to 30 mph. Two-cylinder engines are complex and heavier than single-cylinder bikes ...

Ferrari has filed a patent for an engine with pill-shaped pistons, a radical departure from traditional circular piston designs. While Honda famously experimented with oval pistons in the late 1970s ...

In the video after the break, [Brick Technology] uses LEGO to gain some practical insight into the world of piston engine design ... and build a starter motor, and torque generator.