WENO comparison
Here is a 2D Zalesak disk (an approximation anyways) using a Semi-Lagrangian backwards advection with a Runge-Kutta 4 on a 100x100 grid.
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Last image in video:

Here is a 2D Zalesak disk (an approximation anyways) using a Semi-Lagrangian backwards advection with a Runge-Kutta 4 on a 100x100 grid.
First image in video:

Last image in video:
