because the sashing between the tigers looks like grass or jungle fabric maybe a cloud fabric on top and then water fabric on the bottom and then maybe a piano keys around the whole thing then the sashing fabric again as a think binding of an 1" or 1 1/2"? just a thought and if you need it larger still use the white around the piano keys and you can make the white sides thinner than the top and bottom in white by maybe 1/2" or so. just so that it is a trick of the eye. I am having the same problem with my sons quilt. I am adding an extra row of an other patter on the top and bottom to make it more twin size than square blanky.