With the ripple sailboards becoming increasingly popular, why not treat yourself to a ripple hollow arch too?! Whether you cascade balloons through it, or leave it plain in all it's glory - either way, it'll be a showstopper!
 
12mm high quality MDF, left unpainted ready for you to get your paintbrush out and decorate to match your scheme.
A CNC machine is used to router out the grooves creating the ripple effect. 
Feet are hinged with a cross section slot in each foot for an added weight or sandbag to be attached for extra security if required (see photo attached)