DIY Wonder Woman Cosplay by Becka Noel. Step 6: To create breastplate cups, first I took two large squares (about 10”x10”) of Worbla & heated them together to make a double Unpainted Tiara - Two Viewslayer. Then, I took my half plaster sphere & carefully stretched the Worbla over it. Some people use acrylic spheres or Christmas ball ornaments for this step. Once half sphere Worbla pieces were made, I drew on my design and attached to the very large breastplate piece.