How about firing air at an object through a series of nozzles, measure the resulting turbulence and then solve for shape ;-)
Just a quick solution of a million-dollar math problem (https://en.wikipedia.org/wiki/Millennium_Prize_Problems#Navi...) and you're on your way!
Yes, to be sure you are right. It was just a silly (and, as you point out, mathematically inaccurate) joke.
How about shining a normal light though and just inverting the shadow calculations.. hmm.. has that been done?