Try to do this with your quad! The cup is not attached. If you pay close attention to the cup, you'll notice it sliding back and forth during maneuvers. That's just too cool!
Jago Svensson is a talented aerial photographer and all around tinkerer. I'm sure you'll also enjoy checking out his website here: http://jago.se/jago.se/Projects/Projects.html
I really like his folding quad concept.