Frequently people ask if it's "OK" to make a Zentangle in color. I reply that the traditional tile is done with black ink on a cream background.
No one ever said it was "not-OK" to make colored Zentangle-inspired art work though, right?
And here is some of the finest I've seen.
I recently visited the Franklin Park Conservatory in Columbus, Ohio, where there is a fabulous collection of the glass art of Dale Chihuly. This photo was taken from beneath one of the sculptures.