The half square triangle unit is probably the most commonly used patch in a quilt block -- well it is second only to the square. It is made simply with two triangles, filling up half the square each -- hence the name. Take a quick look through this website, or in any quilting magazine, and you will start to notice that this half square triangle, regardless of its size, is present in more quilts than not.
Free Quilt Block Pattern
I love the Weathervane quilt block. It can be a great teaching aid for beginner quilters because it uses three different quilt patches -- the square, half square triangle and flying geese units. For quilters who like to play with colour, try introducing more fabrics and you will come up with a totally different looking quilt block.
The two sample quilts illustrate how different you can make your project. By added more blocks and setting on point, or using less quilt blocks and adding additional blank blocks you get two totally different quilts. Blank quilt blocks also give you the opportunity to show off your quilting skills.
~ Royal Star