This Creative Grids Square on Square Trim Tool makes creating 4" and 8" square-on-square blocks effortless. Designed by Jean Ann Wright, it simplifies Snail's Trail patterns while letting you customize with different triangle colors. The USA-made acrylic ruler features Creative Grids' signature non-slip grip that holds steady when pressure is applied, plus easy-to-read markings and built-in measurements. Includes step-by-step instructions and a QR code linking to video tutorials. Measures 8-1/2" x 8-1/2".