You'll need:
Eight 5" squares of background fabric
Two 5" squares of fabric #1 (Blue)
Two 5" squares of fabric #2 (Green)
Two 5" squares of fabric #3 (Grey)
Two 5" squares of fabric #1 (Blue)
Two 5" squares of fabric #2 (Green)
Two 5" squares of fabric #3 (Grey)
Two 5" squares of fabric #4 (Zigzag)

Using the directions from this blog post, use the above fabrics to make 16 half square triangles. Arrange them as seen in this picture.

Sew them together into four rows