I feel somewhat stupid here, but I can’t see a (best practice) solution for what seems like there should be plenty of small modules of: on trigger, an envelope goes up, stays up. On next trigger, envelope goes down and stays down.
The only fade in/out modules I find are from Count Modula and Impromptu, but they want to be clicked. Which works for me (the CM one), but it’t be nice to have the Clocked “Run” output do the click for me.
You can simplify with a flip flop. Replace the CVMix/Switch combo with a single Flip Flop. Of course the Flip Flop can go before any gated envelope generator.
When I read your post title I thought you were looking for a one shot LFO like is capable with VCO Lab and VCO Unit. But that is entirely different.