My muse can be a silly, silly creature.
As I was drawing http://www.furaffinity.net/view/13355344/ for no reason other than silliness and sheer perversity it popped into my head to have Constance try and emulate her big sister with a matching rubber inner-tube outfit.
Constance hasn't the skills or patience to build somethign quite so polished yet, so she makes-do: a couple 12-speed tire tubes and some judicious knot-tying, and voila, just as good as big-sister, right?
Of course taking all of the air out of them and removing the valve-stems might have given it a little more of a polished look, but impetuous youth, who has time for all that fiddly stuff?!