Think of an oscillator with 4 simultaneous waveform outputs. Connect all four audio outputs into a VCA module that can mix like an Intellijel quad VCA. Then connect four modulation sources into the CV inputs... maybe a quad LFO like the Xaoc Batumi and set the Batumi to really slow rates. Of course you don't have to mix just one oscillator... or you could mix between effects or even mix CV sources instead of audio.
-- Ronin1973
This is what I usually call "strumming"...like running a pick across strings, but in this case it's modulation signals across multiple VCAs channeling different timbres. It's really an incredible sound, particularly if you pay close attention to the overlap between VCA levels and get a result that sounds like a smooth timbral transition. It's why I can't wait to get my mitts on one of those Buchla 281t reissues, as they have a quadrature capability that's perfect for that trick.