This is a cotton-reel setting, traditionally made with set in corners. The same effect can be achieved by using flippy corner triangles.
I made the settings for these checkerboard blocks the same way.
For the centre of the cotton reel block I used16-patches made with 1 1/2"strips, so they made a 4 1/2"block (4"finished size).
I cut strips to go around it,
* two darker pieces 1 1/2" x 4 1/2"
* two lighter pieces 1 1/2" x 6 1/2"
*four darker squares 1 1/2" x 1 1/2"
Sew the shorter pieces to the sides of the centre block, press seams towards the rectangle.
Draw a line on the wrong side of the squares, from one corner to the opposite corner.
Arrange the squares on the longer pieces just as they are in the picture, and sew on the drawn lines.
For super accuracy, try to sew a whisker on the side nearest the corner, so that when the material is folded back the extra room allows the triangle to sit in the perfect position. Press the triangle back towards the corner. Then trim the extra fabric away, leaving 1/4" seam allowance.
Sew the last two strips onto the block and press.
The corner should look like this.
The blue checkerboard was a little different, because I had the two colours adjacent to each other, instead of on opposite sides of the block. To calculate your own sizes, cut one darker piece the width of your strips and the length of the center block, and from the same fabric strip cut a piece that equals the length of the block + the strip width - 1/2". Cut a lighter piece the same size, then a long piece the width of the strip and the length of the finished block. Cut two squares of darker fabric from the same width strips.
Lots of blocks can be made or set with this method. Attic Windows is a good one, or put an Attic Windows setting round a collection of blocks.