Here's a somewhat heterodox crab canon for three voices, which I've been composing throughout the course of this past evening. In contrast to a typical crab canon for two voices, the three melodic lines (here coloured as themes in their own right) vertically swap positions with each repetition, of which the last three are the retrograde variants. Thus, instead of there being a single mirror point to divide both halves of the canon, the whole line has to be segmented into smaller themes that