The Quarter Square ruler makes quarter square triangles. However, it can also be used to square up blocks to 7.5", or to create a great border. Combined with the Half Square ruler (#GMHS), it makes perfect Flying Geese blocks. Although the Quarter Square and Half Square are both right angle rulers, they are used in different orientations. The Quarter Square is used when the straight grain is on the long leg (hypotenuse). The Half Square is used when the straight grain is on the short leg. 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.