The Good Measure name represents a high quality and accurate measuring system and the good that comes in the form of a donation to breast cancer research for every Good Measure Ruler sold. Make a difference while making something beautiful. Feel good about your choice to purchase Good Measure Rulers - the only rulers with a cause. The 45 degree Kaleidoscope ruler has only one purpose - to make kaleidoscope quilts and quilt blocks. This is a 45 degree Kaleidoscope, so you need 8 pieces, plus 4 corner pieces to make a complete block. We recommend using the Half Square (#GMHS ) to make these corners. All Good Measure rulers are designed to be compatible with each other, ensuring accurate cuts and allowing you to utilize these rulers for all your cutting needs. Each ruler is labeled with its size or the name of the specific job it does. Good Measure rulers are accurate, easy to read and versatile.