Cut triangles from the orange fabric the same size as the yellow triangles. Make half square triangles and sew two of them together to form a flying geese block. You will have a seam down the middle but it probably won't show once the quilt is quilted. Uh Oh, just did the math and your half square triangles are going to be about 1/4 inch short to make a flying geese block at 4 x 8 finished size. Maybe if you play around with seams you could fudge it. I'd try on some scraps first to see if it will work.