Sorry Tam, the formatting did no present the frames proerly. Here they are again without the runner references A, B, C and D.

Frame 1
1 2 3
x - -
- x x
- x x
- x x

Frame 2
1 2 3
x x -
x x -
- x x
- - x

Frame 3
x x -
x - x
x - x
- x -