What license plate ID did Feynman choose for his diagram-covered van? He chose the license plate ID QANTUM.
The unusual spelling was deliberate: QANTUM omits the second “U” from “quantum.” Feynman selected it for the Dodge van he bought in Long Beach, California, in 1975, after discovering that the more obvious physics-related choices QED and QUARK had already been taken.
The van became a rolling expression of Feynman's scientific personality. Its bronze-khaki exterior carried custom murals based on Feynman diagrams, the pictorial notation he developed to represent interactions among particles in quantum electrodynamics. The interior was painted yellow-green.
The plate is easy to misremember as QUANTUM, but that spelling was not the registration Feynman used. After his death, Gweneth sold the van to filmmaker Ralph Leighton for $1. It later went into storage, deteriorated, and was eventually bought by video-game designer Seamus Blackley in 2012.