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 Butterfly Star quilt block is made of easy patches, but can be a test of the accuracy of your quarter-inch seam allowance because it contains a small block (comprised of small patches) inside a larger block. However, none of the individual pieces are difficult to construct.
This block is sewn as a four patch to create the centre of the block, and then constructed as a nine patch for the remainder. It contains the commonly used patches flying geese as well as half square triangles.
By using your imagination for the layout, you can create a stunning quilt. Use the sample quilts shown as inspiration or design your own. Enjoy!