1.5 inch squares - 2 white, 1 dark
3.5 inch strips - 2 white, 2 dark
5.5 inch strips - 2 white, 2 dark
7.5 inch strips - 2 light
Here are all 13 pieces in a blow up of the layout.
Start with a dark square and sew a white square to either side. Press away from the red.
Begin round 3 by sewing 5.5 inch strips of white to the top and bottom of your center square.