I know that there is a formula for cutting squares to make half square triangles. It seems that you make it either 5/8" larger or 3/8...????... I can't recall. If anyone knows the formula, please let me know. If I'm not being clear, it's the sq. you cut and draw a diagional line through the center, corner to corner and sew 1/4" seam on either side to give you 2 half square triangles. Can anyone help me????