Chrissy, sometimes playing with panels that are cut apart into different shapes can be fun! I did that with the Red Rooster Vintage Homestead panel:
http://www.quiltingboard.com/posts/list/22633.page
As long as you match the rectangular pieces with blocks that will make things come out even measurement wise, it is not only legal but lots of fun. Some of the square blocks of that panel I made into the large star centers, some went rectangular lengthwise and some widthwise - using the combo block set of the churn dash and the smaller star enabled me to turn them which ever direction they needed to go to fit.