Cutting a perfect kaleidoscope block is easy, all you need to know is your desired block size. A few quick cuts, and you can create acute and right triangles in 11 sizes and you're ready to stitch. Step by step instructions are attached so you'll have everything you need to use this versatile ruler! 'Kaleido-Ruler Large' by Marti Michell, for 6" - 16" block sizes.