Nancy believed the Winged Square quilt block to have originated in Maine during early colonial days. She said at that time, "geometrical figures such as squares and triangles were the principal medium of expression in quilt blocks." That means this block was trendy in it's day! Blue and white was the original color scheme.
Here is an example of a blue and white Winged Square quilt from the 1930's. It's different from Nancy's block in that the background is blue not white and the right hand side of the block has the blue and white switched around but the left hand side does not. It creates a very interesting diagonal effect.
There is a Winged Square quilt here with scrappy triangle blocks and another version here with a contrasting center square and sashing. A block made exactly like Nancy Cabot's can be seen here. It is in the center of the bottom row.
To make a 6" block, you need three 2 1/2" squares of background fabric and twenty four half square triangle blocks that finish at 1"! The block is put together like this-
You can make eight half square triangles blocks at a time by starting with 3 3/4" squares and following this tutorial. Or you can use these Star Singles printed papers like I did. The advantage of the paper is that I did not have to draw lines on my fabric and I didn't have to start with a perfect square. My fabrics just had to be larger than the paper square which gets trimmed. I found my finished pieces to be very accurate. Look for this product at your local quilt shop or online. They are available in several different sizes.
Of course you can use any other method you like too.
For directions on making a 12" block and some more ideas on how to use the block, go to Quilting Assistant.com.