The Sewing Revolution 5/7 is a 13" circle made of poly carbonate. From the centre point there are circles that graduate out at andfrac14;" intervals.
The circle is divided by 72 degree lines into 5 equal segments (yellow lines) and by 52 degree lines into 7 equal segments (blue lines). Repositioning marks enable further division of the circle.
At each intersection of lines and circles is a small hole for marking with a fine tip marker.