Based off a jpeg at the Texas Scottish Heritage Society. (Why did they save it as a jpeg?) The first blue in their image was only 15 threads wide, I figured that was a typographical mistake given every subsequent blue was 16, even in the repeats.
According to the aforementioned web page, it was designed by June Prescott McRoberts, and adopted as the official state tartan on May 25, 1989.
I place this image in the public domain, in the hope that it will increase interest in tartans and tartan design.
Neale Pickett <neale@woozle.org>