Cut:
2--3 7/8" x 3 7/8" blue, cut corner to corner to make 4 triangles.

2--3 7/8" x 3 7/8" background, cut corner to corner to make 4 triangles.

1--6 7/8" x 6 7/8" green, cut corner to corner to make 2 triangles.

1--6 7/8" x 6 7/8" background, cut corner to corner to make 2 triangles.

4--3 1/2" x 3 1/2" background squares

Assemble as shown