text: #include <cmath>
  #include <matplot/matplot.h>
  
  int main() {
      using namespace matplot;
      auto [X, Y] = meshgrid(iota(-5, .5, +5));
      auto Z = transform(
          X, Y, [](double x, double y) { return y * sin(x) - x * cos(y); });
      mesh(X, Y, Z)->palette_map_at_surface(true).face_alpha(0.5);
  
      show();
      return 0;
  }