Use this to sew together sixteen separate 22.5 degree triangle units to make a full circle, eight for a half circle and four for a quarter circle. Make Fans, Dresden Plates and more with a finished size of 36″. Vertical line can be used to fussy cut stripes or cut half triangles. Angled lines can be used to create intricate blocks. Ruler includes .25″ seam allowances. This ruler also easily slides over fabric until pressure is applied, then the exclusive gripper on the backside of the ruler holds the fabric in place while you cut to eliminate slipping and miss-cuts.