Rhythmus 21 is online with an introduction by the great Jonas Mekas here: http://www.jonasmekas.com/hans_richter.html

For those of us in the motion design trade, this is probably the earliest example of abstract film animation available. Mekas, now 83, gives a great introduction to the piece from an art historical perspective, though we are interested in it as a document of early motion design experimentation.

Meadgallery_invitep1 And don’t forget to poke around his site. Here is a living legend who is reaching out to us, sharing his wisdom and experience from across the years.