The engine that ran backwards. Did you know some engines literally ran in reverse? Certain two-stroke engines in small cars and scooters could run forward or backward, depending on ignition timing. This clever trick meant no need for a reverse gear. The engine just restarted the other way. The Saab 93 rally car even used it, though drivers sometimes stalled and relaunched in reverse by accident. The design worked because two-strokes fire every revolution, making them symmetrical. It was ingeniou