Gyro-X 1967 concept vehicle
"The brainchild of Alex Tremulis, famous stylist and Automobile Hall of Fame inductee, and Thomas Summers, a gyroscope expert, the Gyro-X is a two-wheeled, gyroscopically-stabilized prototype vehicle constructed in 1967. Proposed as a possible solution for future transportation, the two-wheeled vehicle provided many thought-provoking ideas for revolutionizing transportation."
Well, whaddaya know? Hackaday just did an article on this vehicle. That's probably why it was suddenly appearing in my social media feeds:
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