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
This quilt block called Kanzas Troubles is a little trickier than many blocks that contain only squares and half square triangle patches. That is only due to the method of construction. Some of the half square triangles are used on their own, rather than making two pieces into a square. That's not too difficult and by checking the placement of the pieces, this four patch block goes together quickly.
In one of the quilt samples illustrated, you will note that I flipped the arrangement of the patches so that the pinwheel shapes were pointing in the opposite direction. This was done only to achieve the effect I wanted. Experimenting with placement of the large patches will give you the same effect. The creation process for the resultant quilt is half the fun!