* count by 10s to 100
* count by 2s to 20
* count by 5s to 60
* count by 9s to 90
* count by 4s to 40
* count by 7s to 70
* count by 3s to 30
* count by 8s to 80
* count by 6s to 60
* [12] x {10, 2}
* [12] x {10, 2, 5}
* [12] x {10, 2, 5, 9}
* [12] x {10, 2, 5, 9, 4}
* [12] x {10, 2, 5, 9, 4, 7}
* [12] x {10, 2, 5, 9, 4, 7, 3}
* [12] x {10, 2, 5, 9, 4, 7, 3, 8}
* [12] x {10, 2, 5, 9, 4, 7, 3, 8, 6}