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"This car, when combined with a fan cart accessory and a pair of low friction wheels, can travel across a track. The fan will be placed on the back of the car, pushing the air behind it so the car will be pushed forward. Our goal is to create the most effectiv…" - ShruthiKaveti
You also can go to this link and check it out: https://www.thingiverse.com/thing:2970825