"[4] With a duration of 11 to 12 minutes,[1][2] it is one of a group of small-scale works involving string instruments in which Xenakis explores continuously changing pitch curves (glissandi) derived from Brownian motion.
[14] The music covers five octaves, and the player is required to produce quarter tones and quadruple-stop chords, in addition to the extremely difficult contrary motion double-stop glissandi.
[13] Bassist and composer Barry Guy called the piece "an intense work, one that demands you throw yourself into it wholeheartedly," and stated that it "takes you to the limit of your physical capabilities.
"[12] Bassist Robert Black called Theraps "a masterpiece," and remarked: "It is intense, powerful, deep, and beautiful.
"[18] He also recalled that, in his initial meeting with Xenakis, the composer urged him to make the music "much more extreme, savage, grotesque and beautiful.