The easiest way I've found to do triangles is to cut the 2 colors you want one inch larger than the size of the square, put the 2 squares together, mark diagonally, then sew 1/4 inch on each side of the mark, then cut on the mark line, thus you have 2 half square triangles without sewing on the bias edge, press, trim to the required size. Hope this helps.Please feel free to PM me if it's not clear.