In it, Walker invented an international set of symbols called symbolia after researching cartoons around the world (described by the term comicana).

In 1964, Walker had written an article called "Let's Get Down to Grawlixes", a satirical piece for the National Cartoonists Society.

The names he invented for them sometimes appear in dictionaries, and serve as convenient terminology occasionally used by cartoonists and critics.

A 2001 gallery showing of comic- and street-influenced art in San Francisco, for example, was called "Plewds!

"[1] Additional symbolia terms include whiteope, sphericasia, that-a-tron, spurls, oculama, crottles, maledicta balloons, farkles, doozex, staggeratron, boozex, digitrons, nittles, waftaroms, and jarns.