1. Use a pencil to mark a diagonal line on wrong side of each white dot 2-7⁄8" square.
2. Layer a marked white dot square atop a blue dot 2-7⁄8" square. Referring to Diagram 3, sew together with two seams, stitching 1⁄4" on each side of drawn line. Cut pair apart on drawn line to make two triangle units. Press open each triangle unit, pressing seam away from white dot, to make two blue triangle-squares. (To reduce bulk when joining blocks, you may wish to press seams open.) Each triangle-square should be 2-1⁄2" square including seam allowances. Repeat to make four blue triangle-squares total.
3. Using brown dot 2-7⁄8" squares instead of blue dot, repeat Step 2 to make four brown triangle-squares.