Compute isolines/isosurfaces of scalar fields

 Construct isolines/isosurfaces of a 2D/3D scalar field defined by a function,
 i.e. curves over which `f(x,y)=0` or surfaces over which `f(x,y,z)=0`. Most
 similar libraries use marching squares or similar over a uniform grid, but
 this uses a quadtree to avoid wasting time sampling many far from the implicit
 surface.
 .
 This package installs the Python 3 module.