These pics might help to explain the pinwheel layout.
Here are the positive / negative "twin" blocks for these two fabrics. Each block (except for the center one on the quilt) have a "twin" in reverse positive / negative fabrics.
To make the pinwheel - these were so fast and easy (they just look tricky) - you cut two fabric strips to sew together (each strip should be 2.5" wide x 26" long to make a 6" block). Sew the two strips together on the long side to create a 4" x 26" long piece. Then cut the longest side into four pieces that are 4" wide x 6.5" long that should resemble this (pretend it's not cut yet):
Using a straight ruler, cut the piece once from corner to corner diagonally. Be sure that the same fabric strip appears on the same side when cutting and that the diagonals are cut going the same direction on all four pieces (otherwise you won't be able to make pinwheels with the triangles). See photo below:
The 8 triangles you just cut should produce the pieces to make both the positive and negative 6" blocks - you'll have two blocks as shown in the first picture when finished sewing. All the left sided pieces (from the left side of cutting line) should form one block and all the right sided pieces (from right side of the cutting line) should form one block. Two completed blocks.
Assemble as shown:
Hope this was useful!