Paradigmatic analysis assumes that Roman Jakobson's description of the poetic system (1960, p. 358) applies to music and that in both a "projection of the principle of equivalence from the axis of selection on to the axis of combination" occurs. Thus paradigmatic analyses are able to base the assignment of units entirely on repetition so that "anything repeated (straight or varied) is defined as a unit, and this is true on all levels," from sections to phrases and individual sounds (Middleton, ibid).