Here is a modern version of a Mensuration Canon, where the same melody is played simultaneously at different speeds by augmenting or diminishing note values proportionally. In this case, many different rates at the same time. Otherwise, it's just a descending a natural minor scale, played on alternating short and long note values.
Arvo Pärt - Cantus in Memoriam Benjamin Britten
Estonian National Symphony Orchestra Paavo Järvi
@peterquirk
It's one of my favorite pieces by Pärt.
@voltronic Likewise. It's on one of my playlists.