Roussel's most famous works are "Impressions of Africa" and "Locus Solus", both written according to formal constraints based on homonymic puns. Roussel kept this compositional method a secret until the publication of his posthumous text, "How I Wrote Certain of My Books", where he describes it as follows: "I chose two similar words. For example "billard" (billiard) and "pillard" (looter). Then I added to it words similar but taken in two different directions, and I obtained two almost identical sentences thus. The two sentences found, it was a question of writing a tale which can start with the first and finish by the second. Amplifying the process then, I sought new words reporting itself to the word billiards, always to take them in a different direction than that which was presented first of all, and that provided me each time a creation moreover. The process evolved/moved and I was led to take an unspecified sentence, of which I drew from the images by dislocating it, a little as if it had been a question of extracting some from the drawings of rebus." For example, "Les lettres du blanc sur les bandes du vieux billard/The white letters on the cushions of the old billiard table…" must somehow reach the phrase, "…les lettres du blanc sur les bandes du vieux pillard/letters by a white man about the hordes of the old plunderer."