Cut two squares of fabric to the desired size, one in the floral fabric and one in the spotty. Lay the two squares together with the right sides of the fabrics facing each other.
Stitch around the four sides with a 5mm seam allowance, leaving a gap in one of the seams approximately 5cm long.
Trim away the bulk on the corners and turn to the right side. Sharpen the corners and seams, then press.
Finally close the gap left in the seam by hand slip stitching.