The following examples may be useful for understanding various polyrhythms.  Note the use of the bass drum for showing the synch points of the 2 rhythms.

2:3 polyrhythm

2:5 polyrhythm

2:7 polyrhythm

3:4 polyrhythm

3:5 polyrhythm

3:7 polyrhythm

4:5 polyrhythm

4:7 polyrhythm

4:9 polyrhythm

5:6 polyrhythm

5:7 polyrhythm

5:8 polyrhythm