I have a patio/concrete area along the back of the house, divided from the main lawn by a retaining wall (the patio is 2 steps lower than lawn) it is very windy and exposed but gets lots of sun. I want to add some interest (that won't blow away!), what can I do? I am on a budget and have 2 small children and another on the way, so cheap, cheerf and colourful would be good :) Thanks for any abuce you can give a clueless outdoor decorator!