Using the chart above decide what size squares need to be cut. Place the squares right sides together with the lightest one facing you.
Using a marking tool and straight edge, draw a line from corner to corner.
Half Square Triangles: Doubled Up
Flip the piece around. The first stitches will now be on the right hand side of the line. Once again, sew to the left 1/4" away from the line.
Sew on the left side of the line. To help remember this, think of the line as it were the edge of fabric you are sewing 1/4" from.
Place your ruler on the line and cut. With small HST it is sometimes easier to cut with scissors rather than a rotary cutter.
Using your ruler a square ruler, place the 45* angle on the seam. Trim to size.
Press the HST open according to the pattern's directions.