<_description>
Simulates two dimensional incompressible inviscid fluid flow.
-http://en.wikipedia.org/wiki/Euler_equations_%28fluid_dynamics%29
-http://en.wikipedia.org/wiki/Inviscid_flow
+https://en.wikipedia.org/wiki/Euler_equations_%28fluid_dynamics%29
+https://en.wikipedia.org/wiki/Inviscid_flow
Written by Stephen Montgomery-Smith; 2002.
</_description>