This is a unique delay with a normal and a reverse delay feeding into a feedback network. Syncable to MIDI with independent pans, this delay can create push/pull sounds and many, many interesting textures.
I haven't done a free algorithm for a while, so I'm making this one free.
https://godlike.com.au/index.php?id=420
Look down the right hand margin and look for Zig Zag Delay.
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