plot3d (sin(2*theta)*cos(phi), [theta,0,%pi], [phi,0,2*%pi],
  [transform_xy,spherical_to_xyz], [grid,30,60], nolegend,
  [pdf_file,"./plotting22.pdf"]);
plot3d (sin(2*theta)*cos(phi), [theta,0,%pi], [phi,0,2*%pi],
  [transform_xy,spherical_to_xyz], [grid,30,60], nolegend,
  [png_file,"./plotting22.png"]);
