I think I would do a 'dwirl'. The name comes from Thepajamaquilter. It looks like a topographical map and is VERY fun and easy to do. Here is a picture of a quilt that used it. Practice on a white board before you try it on your quilt. Don't put your elbow or wrist down..you are teaching your shoulder!
http://blog.maryquilts.com/2011/11/10/i-did-good/