Any idea how the rolling percussion effects on the studio version of Videotape were achieved? Sounds like several sounds layered on top of one another, gradually falling out of sync.

A Max patch could do it, so perhaps that. Honestly, there are so many ways that the band could have made those sounds (Max, Protools, layering drum machines or actual drum playing with each go slowly changing the speed) that I couldn’t really say for certain. All of those seem to be viable options.