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
The Art Square quilt block is a great starter for the beginner quilter. It can be made as a larger block to get the idea of how patches go together. For quilters who want more of a challenge, you could make the same block but in a smaller scale. This will really enhance the precision of your piecing skills.
The Art Square quilt block contains simple patches -- only the square and half square triangles to create those flying geese units, which are so common to many quilts.