Algodoo

How does this machine work? It uses the main wheel's torque and air friction to power up the engine. Then the both right and bouncy wheels bump which turns back the top wheel layer. Then the left wheels bump adding a little speed. This small beauty can go up to 3.5 m/s.

Be careful: The bouncy wheels can bump too hardly and it may damage the engine.

"Algocard" Another try