Step 1: Cut a square piece of fabric and fold diagonally.
Step 2: Cut diagonally.
Step 3: Place the triangles right sides together and sew together using a 1/4" (0.5cm) seam allowance.
Step 4: Press the seam open.
Step 5: On the wrong side of the fabric mark lines 1 1/2" (4cm) apart. Parallel to the longer sides of the fabric.
Step 6: Fold the outer short edges towards the middle, right sides together. Offset the lines so that a and b meet in the middle. Make sure the other lines meet.
Step 7: Pinch the fabric together and sew.
Step 8: Start cutting your strip following your marked lines.
Step 9: Take your cut bias binding, fold the strip in half lengthwise, wrong sides together, and press. Then open out, fold in the outer edges towards the center crease.