Ave sanctissima, by Philippe Verdelot, sung by Quire Cleveland, dir. Ross W. Duffin

Ave sanctissima, by Philippe Verdelot, sung by Quire Cleveland, dir. Ross W. Duffin, at Holy Trinity Lutheran Church, Akron OH, on Oct. 29, 2017.
Ave virgo sanctissima exists in various sources with conflicting attributions, but it seems most likely to have been by Philippe Verdelot. In this case, three voice parts begin simultaneously, but each is followed by canonic part singing a fourth higher. The separation at first is just one measure, but after a cadence and a pause, the canon starts again at a distance four measures. This seems simply to alternate a trio with its answer four measures later, but eventually the leading voices continue instead of resting and join together with their following counterparts. Thus, from three notated voices, a texture of six is created. Remarkably, the fact that it is entirely canonic is not the predominant impression for listeners.

[@ludustestudinis]

Without the explanatory text I would not have noticed the structure. IMO, this is true art: music that pleases both the superficial listener and the expert.