1. Sew red print triangles to opposite edges of a green print 9" square (Diagram 1). Press seams toward triangles. Add red print triangles to remaining edges to make a block center. Press seams toward triangles. The block center should be 12-1⁄2" square including seam allowances. Repeat to make nine block centers total.
2. Use a pencil to mark a diagonal line on wrong side of each burgundy print 2-1⁄2" square.
3. Align a marked burgundy print square with one corner of a block center (Diagram 2; note direction of marked line). Sew on drawn line. Trim excess, leaving 1⁄4" seam allowance. Press open attached triangle. Add marked burgundy print squares to remaining corners; trim and press as before to make a block. The block still should be 12-1⁄2" square including seam allowances. Repeat to make nine blocks total.