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 Rocky Garden quilt block is a basic nine patch block that uses the half square triangles both in patches to make squares as well as individual cut pieces to add on to other patches. You also get to hone your skills making flying geese units. All in all this quilt block is a good choice for teachers to use in a beginner quiltmaking class.
The sample quilts illustrated feature one quilt set on point, while the other quilt has blocks set side by side. This last quilt mentioned uses blocks with two of the fabrics reversed in half of the constructed blocks, so that you get a different effect in your final quilt.