Two clocks.
Same room.

A polyrhythm is when two or more rhythms play simultaneously and their periods don't align. They share a start point. They share a tempo. Everything else is negotiable. The tension between them is the music.

POLYRHYTHM

Multiple truths. One time.

BPM90

LAYERS

3 beats●

4 beats●

ratio: 3:4 · cycle: 2.67s

HOW IT WORKS

Each ring is a rhythm.

The dots are beats. Evenly spaced around the circle. The cursor rotates. When it hits a dot, it fires. All rings share the same rotation period. But a ring with 3 dots fires 3 times per cycle. A ring with 5 dots fires 5 times. They started together. They will meet again. Eventually.

The math.

LCM(3, 4) = 12. After 12 beats, the pattern repeats. LCM(3, 4, 5) = 60. After 60 beats. LCM(5, 7) = 35. These two won't agree for a long time. The longer it takes to repeat, the more interesting it is. That is not a metaphor. It is just true.

COMMON RATIOS

3:2

hemiola

Ancient Greece → West Africa → Jazz

3:4

cross-rhythm

Standard. The heartbeat of most everything.

4:3

cross-rhythm

Same as above. Different perspective.

5:4

quintuplet

Rare in Western music. Common in Bulgaria.

7:4

septuplet

Used by Radiohead. Used by bees.

2:3:4

compound

Found in Gamelan orchestras. Found in architecture.

"The beat you expect is not the beat you hear. That gap is where music lives."