HST is a simple block that is quick to make, can use up lots of scraps, and has numerous variations. It is one of my favorites. I usually pick two colors… a light and a dark. For this example, I am using blue as the dark and yellow/gold/tan as the light. I have a stash of scraps that includes a lot of 5 inch squares, so I decided to make a bunch of these blocks to use them up.

On the back side of the light squares, mark two lines diagonally across 1/2 inch apart as shown in the photo to make two seam lines.

Layer with a dark square, right sides together, and stitch along each line. Cut along the center diagonal between the seam lines to make two half square triangle blocks.

Trim to 4 1/2 inches square, keeping the seam centered on the diagonal.

Make a bunch of these blocks with your scraps. Since they are four inches finished size, 100 of them will make a 40 inch square quilt.

There are many setting variations that can use this simple block. Here are a few you might want to try, as mocked up on my design wall:

Basic half square triangle set:

Pinwheels (works well with sashing between the pinwheel squares)

Diagonal stripes

Zigzag stripes

Expanding squares

Expanding spiral

There are probably others. And the settings would be more distinct with a more careful selection of values; some of my light scraps are a little too busy or dark, and some of my darks are not quite dark enough. I will probably swap some blocks out before I finish this quilt.