On 1979, the Argentinean writer Julio Cortázar published "Un Tal Lucas" ("A Certain Lucas"), a book of connected short stories, all of them having a given Lucas as the central character. The book is written in the first person, and each story verses about one of the Lucas' many abilities and manners, such as his patriotism, speeches, working habits, and so on.
The story of interest to this write-up is one called Lucas: his sonnets, which tells about the sonnets Lucas used to write from time to time. The sonnet Cortázar chose to illustrate Lucas' writing skills is anything but trivial. The "Zipper Sonnet", as Lucas labeled it, is a piece of writing that aims to be reversible, being "parseable" both in the normal manner, from the first verse down to the last, and also backwards, from the last verse through the first ("last" and "first" as in the usual sense). That was not Cortázar's first incursion into the realm of literary inventiveness, as some two years before he published his famous Rayuela, a romance that bears the peculiarity of having not one thread of reading, but two (at least, as the chapters of that book formed something very similar to a single linked list, where each chapter pointed to the following, which was not necessarily the "physically" subsequent). The Zipper Sonnet is something like that, only it has only two fixed ways to read it. See it for yourself:
Zipper Sonnet
de arriba abajo o bien de abajo arriba >>
este camino lleva hacia sí mismo >>
simulacro de cima ante el abismo >>
arbol que se levanta o se derriba >>
quien en la alterna imagen lo conciba >>
sera el poeta de este paroxismo >>
en un amanecer de cataclismo >>
naufrago que a la arena al fin arriba >>
vanamente eludiendo su reflejo >>
antagonista de la simetria >>
para llegar hasta el dorado gajo >>
visionario amarrandose a un espejo >>
obstinado hacedor de la poesía >>
de abajo arriba o bien de arriba abajo >>
"It's not that it works? It's not that it is...that they are - beautiful?" - rejoices ironically Cortázar, cloaked behind Lucas' words of self-compliment. And I can only agree: First, you really can read it backwards, and it still makes sense. It's just like reading two poems, with different words that are the same; and second, whatsoever path you pick to read it, up-down, or down-up, the sonnet is saying the very same thing, and it is about the fact that it is a sonnet that can be read in two ways.
Nifty? Well, a few years later, Cortázar's friend Haroldo de Campos, a Brazilian poet, set another version (or "contravention", full of licenses, as Haroldo puts it) of the Zipper Sonnet. In the words of Cortázar, his friend enhanced sharply the two-way characteristic of the sonnet, and despite the fact that Haroldo pities the cost of violating one or two rimes in the process of translation by putting approximative "sound likes" on place of it, both of them seem to be satisfied with the Portuguese language outcome, which is:
Zipper Sonnet
de cima abaixo ou já de baixo acima
este caminho é o mesmo em seu tropismo
simulacro de cimo frente o abismo
arvore que ora alteira ora declina
quem na dupla figura assim o imprima
sera o poeta deste paroxismo
num desanoitecer de cataclismo
naufrago que na areia ao fim reclina
iludido a eludir o seu reflexo
contraventor de própria simetria
ao ramo de ouro erguendo o alterno braço
visionario a que o espelho empresta um nexo
refator contumaz desta poesia
de baixo acima ou já de cima abaixo
Furthermore, the sonnet's protagonist, which is the hypothetical one that writes the poem down, encounters his antagonist in himself, who re-writes all things up every time the poem comes to the end - twice doomed Sisyphus, whose punishment dwells not in the invariable failure of his mission, but in its utter success...