The isosurface of the initial value and isosurfaces obtained from PDE transforms of different orders. (a) Initial value, u(r, t = 5000) = 1.0; (b) The isosurface after the PDE transform with 2m = 2, u(r, t = 5000) = 0.4; (c) The isosurface after the PDE transform with 2m = 4, u(r, t = 5000) = 1.0; (d) The isosurface after the PDE transform with 2m = 6, u(r, t = 5000) = 1.0; (e) The isosurface after the PDE transform with 2m = 8, u(r, t = 5000) = 1.0; (f) The isosurface after the PDE transform with 2m = 10, u(r, t = 5000) = 1.0.