EQ has it right. I don't see how it could be paper pieced as one. Together, there is always a raw edge somewhere. Though someone else might see how. If it were me, I would make a large diamond and two small triangles. I would start with A3, add A2, A4 and A1. Then I would add A5 the big triangle. On the two smaller triangles, you can either do the same way starting in the center or you could do A7 add A12, A13 then A11. Then A6, A9, A10 adding A8 last. I would press and trim. Using the seam allowance guides to piece the triangle together. It will be interesting to see how someone else would paper piece it.