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 Buttercup quilt block is one of many different flower blocks. This is a great block for beginners because it contains only squares and half square triangles. For those of you who want to make it more challenging, then I would suggest you make this quilt block as a 6 inch version.
The sample quilt layouts illustrated demonstrate that by simply rotating several of the quilt blocks you can produce a totally different look. One of the quilts shown sets the blocks side-by-side while the other lays the quilt blocks out on point.