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 Rat Pack quilt block looked familiar to me and then I realized it seems like a less complicated version of a block called Birds in the Air. Both blocks are four patches, but the Rat Pack block would be a better choice if you are just learning how to make a quilt. It contains only squares and half square triangles, but you have to also play with the individual triangle pieces in places. An interesting challenge.
Don't let a simple block fool you into thinking your quilt will be boring. As you can see from the sample quilts illustrated, by playing around with rotations of the blocks, I came up with some interesting quilts as a result (if I do say so myself)! See what your creativity can come up with using this interesting block.
~ Birds in the Air
~ Cat's Cradle