OBW triangles are cut by lining up 6 layers of the same fabric so that the same design element is at the same place on all 6 layers. Strips are cut from the layers, and then equilateral triangles are cut from the strips. Then the 6 identical pieces from one triangle (all 6 layers) are put together to form a kaleidoscopic design. Your pieces do not look like they are for a OBW. They might, however, be for a hollow cube, which is included in some OBWs. The author of the books for OBW is Maxine Rosenthal.