Creative Grids Half Sixty Triangle Ruler bgut_odd and this thread bundle has

and this thread bundle has it in spades

Finished size: 18" x 15" each

lint brush

With the sloping lines through the center of the square

when stronger stitch support is required

Creative Grids Half Sixty Triangle Ruler bgut_odd and this thread bundle hasUse the Half Sixty Triangle Ruler from Creative Grids to cut setting triangles for the Creative Grids 60 Degree Triangle Rulers. Sew two triangles together to create a 60 degree triangle or half rectangle. You can also cut a wide variety of shapes that will fit into a 60 degree grid. The ruler slides over fabric until pressure is applied. Then, its grip feature holds the fabric in place while cutting, eliminating slipping and miscuts.