Wikipedia
Dynasphere
The Dynasphere (sometimes misspelled Dynosphere) was a monowheel vehicle design patented in 1930 by J. A. (John Archibald) Purves (7 August 1870 – 4 November 1952) from Taunton, Somerset, UK. Purves' idea for the vehicle was inspired by a sketch made by Leonardo da Vinci.