Half square triangles are amazing — one of the most beautiful and versatile quilting blocks, they’re also among the easiest to make.  I especially love the look of a values quilt done in half square triangles.  The contrast between the colors of your triangles allows you to create visual interest and depth.  Here are some photos to show you what I mean.  The squares are in the same position in each of these photos, just rotated so that the light and dark sides make different patterns.

You can see more variations of half square triangles in finished quilts in this Flickr gallery.  Ready to try it yourself?

You’ll want to start with simple squares.  I like to use charm packs, packs of precut five inch squares that usually include prints from an entire line of fabric.  (The fabrics used here are Fossil Fern by Benartex, a fabric line that’s been in print for an amazing 15 years!)

Sort your squares into three piles by color value: light, medium and dark.  Then pair up colors by taking one each from two different piles, placing the lighter on top with right sides facing.  Draw a diagonal line from one corner to another.  (This line won’t be seen, so feel free to use a regular pencil if you like.)

Use the line as a guide to sew a quarter inch seam along one side,

then the other.

Cut along the pencil line and you’ve got two new squares.

Press the seam open.  Don’t worry about those wonky little bits that stick out, they’re about to be trimmed off.

I’ve started with a five inch square, but I’m going to trim it down to 4.5″.  This will allow me to even up the square nicely.  I like to use a square template for this because it’s got handy lines for me to follow, but you can also use the lines along your cutting mat.  For the first cuts, I line up the center seam with a diagonal line on the template and make sure the fabric under the template is still larger than 4.5″, then cut along the right and top edges.  Having that perfect center line will make piecing much easier later.

Flip the fabric around so the two uncut edges are at the right and top again.  Line up the center seam with that diagonal line and make sure the bottom and left edges are at the 4.5″ marks.  Careful cut the top and right sides.

This will give you a half square triangle made of two perfect triangles.

You’re ready to set them out in different patterns and see how you like them best!  Here are a few of my own half square triangle quilts so that you can see how versatile they can be.  (You can find more details through my Quilts page.)