It's a windmill, but the extra pieces on the sides make it knit up big, as it were. Here is what you do.
Sew the remaining rectangles onto the side of each rectangle with a triangle corner. Make sure the triangles are all 'going the same way'!
Lay out the pieces so that you get a windmill in the centre and sew together.
You will have a little waste on each side, so trim to square it. the beauty of this method is that you can use any size squares you like. Mine were 5" charm squares and produced a block of 8 1/2" (8" finished). Have to get on and make some more!