It seems like we can't get away from set in seams. This block involves quite a bit of that again.
I explained set in seams in quite a bit of detail in B-9. Just follow along from the point after I cut the corner out (you obviously don't have to do this over here.
Print or trace your block diagram (or at least the center bit) onto freezer paper. I did the whole block because I find that ironing freezer paper to the back of even non-foundation pieced sections helps reduce distortion of the fabric.
Foundation piece the center section and trim the seams to exactly ¼". Cut out the other sections, remembering to add the 1/4" seam allowance all the way around each section.
Attach the little side triangles to the foundation pieced section.
Attach the first two side sections as in the photograph. The most important thing in assuring accuracy here, is to line up the ends of the seams properly. Mark the seam lines on the fabric (or use freezer paper as a guideline) and pay special attention to the ends of the seams (i.e. where you stop sewing).
Attach the remaining two sections.
Applique the little diamonds into position on the block using your favorite method. I used the freezer paper inside method I explained in block E-1. I find that it gives me the sharpest corners. My little diamonds are a little wonky, but I'm not changing it.