Two Bank Switched Multiple

Two banks of four jacks, with a red button between them. Each bank is four jacks wired together: patch one signal in, take three copies out.

Button out, you have two separate multiples. Button in, the banks join into one eight-jack multiple (one in, seven out).

Patch into the top bank and out of the bottom one, and the button becomes a performance mute: tap it to drop a part in and out, cut a clock, or kill a modulation source.

Passive: no power, no ribbon cable, 15 mm deep.

Available as a DIY kit (30 through-hole solder joints, a good first build) or assembled.

Open hardware (CC BY-NC-SA 4.0). Manual and assembly guide:
https://schenktronics.com/docs/st-01/

https://schenktronics.com/product/st-01/