This one is shown using a mix of greens in the foreground and a mix of light beiges and tans in the background.
The actually colors aren't as important as the contrast in value between the foreground and the background. The foreground needs to be dark and the background needs to be light.
I played with the block and came up with various combinations, including the 3 below.
The half-square triangles are 3"x3", so the block is 12"x12", and the lap quilts are 54"x78".
You might want to play with the block to see what you can come up with.