Custom pattern, with several variations, each a little different, some with an inner ring of 13 inches, others without, so look carefully at the variations.  This pattern sent as a pdf file with a large page (20 x 20 inches) the black and white pattern on this is 16x16, and a third page which is black and white but printable on letter size paper and enlarged with a program or xerox to any dimension you want.   Color can be requested separately.