… that if you cut the piece up into sequential groups of 12 notes (whatever their length), that there will be one of every kind of note within each group?
I think that’s what it means. It sound somewhat fun to write — sort of like a tavern puzzle, but crap to listen to and vaguely pointless, to be honest. It sounds to me like making a meal based on using a tiny bit of 12 randomly chosen spices. Sure, it’d be sort of neat to give it a try, but I’d rather not eat the results.
I just wish that someone would explain it better, because I think that’s what it means. Take a piece of music by Schoenberg or one of those cacophonous dudes and a scissor, and cut the music into pieces every 12 notes. Within those little bits of staff, you should see one of every kind of chromatic note.
I don’t know if Schoenberg is up on IMSLP or not, but if he is, I suppose I could try it and see if it works.