vimsynth/modules/switch
A gate turns a signal on and off — or picks between two. Leave b unpatched (it normals to silence) and it is a mute; patch b and the same gate chooses between a and b. Crossfades, so it does not click.

SWITCH to get this card.Down the left edge of the card, top to bottom.
latch on, each rising edge flips it instead.Down the right edge, in the same order.
a or b, crossfaded so there is no click.Left to right across the face — the dials in the picture.
The full reference — every parameter curve, the patching notes and the worked examples — lives in the manual: docs.vimsynth.com/modules/switch. In the app itself, :help SWITCH opens the same page without leaving the rack.