Algodoo

This engine is semi-scripted and actually uses & burns fuel. It is completely phunlet-safe, and is only secured to the background with the orange squares.

The engine already has momentum, and will begin generating torque a small amount of time after starting the scene.

WARNING: Requires a fairly ridiculous amount of memory & processing power because the scene contains hundreds of circles at any given time which are used to simulate fuel and exhaust.