Panel blocks (all sizes are approximate): large horizontal 24 3/16 x 18 3/16 including 3/16 white border; large vertical 14 3/16 x 19 3/16 including 3/16 white border; two small horizontal 14 3/6 x 11 3/16 including 3/16 white border; small vertical 10 3/16 x 12 3/16 including 3/16 white border. There is 1/