The quest for the one wheel vehicle!

For years, people have tried to devise a simple wheel device to transport people.

In WWI, they envisioned a large single wheel vehicle that would serve as a tank:



And in recent times, many have tried to make a drivable wheel:



And this one from South Park:


The “IT” from South Park

But here is a real working prototype drivable wheel vehicle named the dynosphere from the 1930’s: