The required materials to build a car similar to the one in this tutorial are about-
-One 12x12in sheet of acrylic.
-One rubber band.
-Recommended: Rubber material to put onto wheels for traction.
-Full Spectrum laser cutter
Step 1: Design philosophy
When you pull the car backwards, the rubber band is forcefully pulled around the axle by the torque that you indirectly applied to the wheels. This stores elastic energy in the rubber band. So when you release the car, the rubber band will quickly unwrap itself, applying torque to the back axle, sending the car forward.