"Cifra" ("cipher"), Octavio Paz. From the collection of six "Topoemas" ("topoems") published in 1968. ("Topoem = topos + poem. A spacial poetry, in contrast to temporal, discursive poetry. A recourse from discourse."1) On this topoem, Paz comments:

Originally, the word cifra meant, in Spanish, zero, and not merely any digit. The English cipher still retains the original meaning. Cifra / cipher comes from the Arabic sifr (zero, void), which is none other than "the Sanskrit word sunya, derived from the root svi, to swell. Our ancestors, with a fine instinct for the dialectical nature of reality, frequently used the same verbal root to denote opposite aspects of a situation." (Edward Conze, Buddhism). Cipher (empty-full) → Calm.2
1, 2 Author's notes, The Collected Works of Octavio Paz, pp. 648-49.