Wow, your concept is so good! I can see staffs and other curved images jumping through my brain. But I have no idea how to do it.

I myself steer clear of curves as of right now. I'm having enough problems with straight! But good luck to you and I'm sure your daughter will love anything you make regardless of straight or curved. I'm with Rebecca in the idea that straight lines can look curved if you place them strategically. I made a tessalated cat design with 4 cats with their curved tails intertwined, it looks curved, but it was all made from squares, rectangles and triangles. Look on my blog for the picture of the cats http://www.soooowht.blogspot.com/