janken: 20 HP, a three-way mixer where nobody ever wins, by daylight noise

The contest

Patch three parts of one song into ROCK, PAPER and SCISSORS. Each ducks the one it beats: paper covers rock, scissors cut paper, rock blunts scissors. So none of them can stay on top. One part takes the stage, the one that beats it comes up and takes it over, then the one that beats that, round the triangle, clockwise on the panel. The mix never settles. Janken is rock, paper, scissors in Japanese.

ROCK, PAPER and SCISSORS: the three inputs. The contest runs on its own and sets their levels, so a loud part bites no harder. An empty input still takes its turns, as silence.

BITE: how hard the one on the stage ducks the others. Down, all three are always in and the balance turns slowly; at noon the beaten part sinks to about -32 dB; full, the winner plays alone and each turn is a hard cut. BITE CV adds to it.

The turns

A fresh deal starts with all three level and a flurry of quick turns. Then each part holds the stage a little longer than the one before, as long as SLOW lets it, until you throw again.

PACE: a turn every half second, a beat at 120, up to one every three minutes.

SLOW: none, a steady rotation; full, each turn twice as long as the last, up to 64 times the first. SLOW CV adds to it.

CLOCK: with a clock in, turns change only on its edges, and PACE picks how many clocks a turn lasts, 1 to 64.

THROW: the button or a trigger deals the hands again: equal shares, the turns short again.

The read

JANKEN works out each turn before it comes, so it can tell you who's next. A little before every change, the ball in the middle comes up and a ring lights round the hand about to win, both in a cold light, before you hear it. It's never wrong.

READ: a gate from the read to the turn, a quarter of a turn early (with a clock, a quarter of PACE's clocks). Patch it to a fill or a riser.

The ball says when, the ring says who.

What comes out

Each hand's window is lit warm, as bright as its part's share of the mix.

WIN: three gates, one beside each hand, high while that part holds the stage. Exactly one is high at a time.

OUT L and OUT R: the mix, SCISSORS on the left, ROCK in the middle, PAPER on the right, as they sit on the panel.

The panel

Twenty HP, every part on the line's staggered grid and mirrored about the middle. Three hand shadows sit at the corners of a triangle round the ball, each in a round window of circuit board lit from behind, with gold dots falling away from each pool of light.

ROCK at the top and its hand under it; SCISSORS and PAPER down the sides, at the ends of their hands' arms.

PACE, SLOW and BITE in the gaps between the hands, THROW's button at the foot.

READ, CLOCK, BITE CV and OUT L down the left; SLOW CV, THROW and OUT R down the right; a WIN beside each hand.