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.
Churn Dash - a Variation
Free Quilt Block Pattern
The Churn Dash quilt block is also known as Monkey Wrench. The Monkey Wrench block was featured as one of the quilt blocks that helped slaves find the escape routes along the "Underground Railroad". So, it has some interesting history.
This variation adds some extra half square triangle pieces to the original 10" block, which is nice for those wanting to express a little more of their skills. However, this version is still a very easy block to make.
The two sample quilts illustrated both feature the quilt blocks on point but vary slightly as additional corners have been added to one version while sashing and extra blank blocks are features of the second quilt. All in all, there is no limit to your creativity for your own heirloom quilt.
See also: Churn Dash