The center is now precut to give you a smooth surface for sewing. Lori Holt designed her Seams Sew Easy™ Seam Guide for an accurate 1/4in seam and for constructing easy corner triangles. This tool saves time by not having to mark lines on your fabric when sewing half square triangles, flying geese or snowballs. The center circle of the guide is also marked with 1/2in grid lines for a wider seam allowance. This is a seam guide that temporarily adheres to the bed of any sewing machine. These grid lines also help to ensure correct placement when adhering to your sewing machine bed.