tangle letters feedback

So remember the zentangle letters from the start of last year (and if you have not been reading that long this is the link) http://applesloveorangespdx.blogspot.com/2011/09/first-lessonsthe-good-and-not-so-good.html

So it came down to I loved the work the kids did on making the letters like the one above, but I was less than excited about the mini stamps they made and printed around the boarder.

it was just too hard for the kids to get a good clean print each time and keep the prints eve and on the black paper.

So 6th grade is about to do this lesson and I just don't know what to have them do with the boarder area on the background paper. I feel like it is a bit too boring if we just leave it black, but I don't want it to get too distracting from the letters they make....any ideas?