clear; clc; close all;
% NOTICE: Your MATLAB version should be at least R2019a !
% --------------------------- functions -------------------------------
f = @(x, y, z)(x.^2 + 2.25*y.^2 + z.^2 - 1).^3 - ...
x.^2.* z.^3 - 0.1125*y.^2.*z.^3;
g = @(x, y, z)(sqrt(x.^2+y.^2)-2.5).^2 + z.^2 - 0.4^2;
% -------------------------- generate data ----------------------------
t = linspace(-5, 5);
[x1, y1, z1] = meshgrid(t);
[x2, y2, z2] = meshgrid(t);
val1 = f(x1, y1, z1);
val2 = g(x2, y2, z2);
[p