Gomringer's "From Line to Constellation" manifesto is the source for one of the best definitions of first wave Concrete Poetry, as well as containing the coolest German word that I try to work into any conversation on visual poetry: Denkgegenstanddenkspiel.
"So the new poem is simple and can be perceived visually as a whole as well as in its parts. It becomes an object to be both seen and used: an object containing thought but made concrete through play-activity (denkgegenstanddenkspiel), its concern is with brevity and conciseness. It is memorable and imprints itself upon the mind as a picture. Its objective element of play is useful to modern [humanity], whom the poet helps through [his/ her] special gift for this kind of play-activity."
Read the whole manifesto here. Incidentally, Gomringer is also credited with one of most controversial statements about Concrete Poetry: "Concrete poetry has nothing to do with comic strips" (cited in Mary Ellen Solt's Concrete Poetry: A World View, 10)
And I love this playful photo of Gomringer in front of his most famous piece: