This document should help you understand more and explain!
http://file.scirp.org/pdf/CE20120200003_78369835.pdf
Hope this helped!
:)
The first Roman theatrical performance in 240 by
Jan Myers creates movement in her quilts through repetition and alternation of colors. Only after looking closely do we see that, like the keys on a piano, every square in the quilt moves up a note in value. Laid over the diagonal "cylinders" of graduated color is a beige grid that appears lighter or darker, depending on the colors behind it. Our eye races across this quilt, up and down and over the rolling cylinders.