This block takes us back to practice with Y-Seams.
This is also a good block for practice working with seams pressed open.
I found that it was easier to assemble and looked better that way.
You can find instructions for one 18" version here, at the Quilter's Cache:
I made mine as a 12" block and pieced it together in a different order.
The attached file includes templates (my preferred cutting method), rotary cutting instructions, and piecing diagrams for my 12" version.
For those who simply cannot bear the though of another Y-Seam, there is a brief example of assembly using squares and half-square triangles.
This block is not a good candidate for paper/foundation piecing. It wouldn't be impossible, but it would not be a practical approach.