Raymond Queneau was one of the leaders of a group of ten--primarily writers and mathematicians, primarily French--who founded a group, "Ouvroir de Littérature Potentielle" ("Workshop of Potential Literature"), that eventually became known as the Oulipo. Queneau described potential literature as "the search for new forms and structures that may be used by writers in any way they see fit."
Queneau (1903-1976) was also a novelist, perhaps best-known for Zazie dans le metro, also made into a film, and Exercises in Style. His poetry often involves puns and other linguistic devices that challenge translation. The French title of the following poem is "Cygnes"--and "cygne" (which is "swan") is a homophone for "signe" (which is "sign"). Here is a translation of "Cygnes" by Daniela Hurezanu and Stephen Kessler (from EYESEAS, Black Widow Press, 2008).
An early example created by Queneau was Cent Mille Milliards de poéms (one hundred thousand billion poems)--a collection of sonnets designed so that each first line may be read with any of the second lines which may be read with any of the third lines, and so on. The Internet offers samples of Queneau's masterpiece (English translation by Stanley Chapman).
When One made love with Zero
Spheres embraced the torus
Prime numbers stepped forward
Their hands reaching for fresh sycamore
And simple fractions mortally wounded
Lay down in the torrent of mute decimals
When B made love with A
Paragraphs embraced blushing
Commas stepped forward
Stretching their necks over the iron bridges
And the alphabet mortally wounded
Collapsed in the arms of a mute question mark