Polyrhythms are two or more independent rhythms which are played simultaneously against each other. There are various types of polyrhythms but the most typical are Just Intonation rhythms. Below is a gallery of all polyrhythms up to 13-limit.
2-limit polyrhythms[]
2/1[]
Listen to it slow:
Listen to it Fast:
3-limit polyrhythms[]
3/2 ----------------[]
Listen to is slow:
Listen to it fast: