What is the real life use of hyperbola? The point of this question is to compile a list of applications of hyperbola because a lot of people are unknown to it and asks it frequently.

Applications of hyperbola
Dulles Airport, designed by Eero Saarinen, has a roof in the
shape of a hyperbolic paraboloid. The hyperbolic paraboloid is a three-dimensional 
surface that is a hyperbola in one cross-section, and a parabola in another cross section.
This is a Gear Transmission. Greatest application of a pair of hyperbola gears:

And hyperbolic structures are used in  Cooling Towers of Nuclear Reactors.. Doesn't it make hyperbola, a great deal on earth? :)
