I googled "white house chandelier" & got a closeup. It looks like the chains/wires are for the purpose of keeping this outdoor chandelier from blowing in the wind (& possibly destroying itself). So the chains/wires aren't just hanging loose, and hence are neither parabolae or catenariae. But the catenary (~ e^x) function is an appropriate metaphor for the spending encouraged by every occupant of this building. At 12:03 PM 3/18/2013, James Propp wrote:

Is the hanging chain on the back of the $20 bill mathematically correct? It looks more like a parabola than a catenary to me.

Jim Propp