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 Rolling Wheel quilt block is a great teaching aid to introduce the three quarter square triangle patch. This unit is a bit of a misnomer because yes, there are three triangles in the patch, but not all of the triangles are quarter square triangles. However, this patch is a useful one in order to make a pinwheel type of quilt block. Have fun with this design and watch secondary designs emerge as you lay out this block in a variety of ways.
The sample quilts show two different results by setting the blocks "on point" rather than straight across. By changing up the setting triangles, you get a totally different look.
~ Rolling Pin
~ Rolling Rock
~ Rolling Stone