Prepare triangles for piecing with perfect alignment using Fons & Porter Triangle Trimmers.
1. With right sides facing, lay 1 light triangle atop a square, aligning square corners. The triangle tip extends beyond the square. Lay each triangle trimmer atop the triangle to see which is the right one to trim triangle tip even with the square. To fit triangle exactly to the square, use the pink trimmer to trim the tip perpendicular to the short side of the triangle (Photo A). Stitch the triangle to one side of the square as shown.
2. Open out triangle and press seam allowances toward triangle. With right sides facing, lay the second triangle atop the joined pieces. Again lay each triangle trimmer atop pieces to determine which will trim the triangle tip to exactly fit the stitched pieces. Use the blue trimmer to trim tip perpendicular to long side of triangle (Photo B). Join the triangle to the adjacent side of square. Open out triangle; press seam allowances toward triangle.