% illustration of a surface of revolutionfunction main()   % the number of data points. More points means prettier picture.   N = 300;   a=-3; b = 4.3;   % polar coordinates   ZZ = linspace(a, b, N);   TTheta = linspace(0, 2*pi, N);   % mesh grid   [Z, Theta] = meshgrid(ZZ, TTheta);   % the curve we will revolve   R = cos(Z)+2;       X = R.*cos(Theta); Y = R.*sin(Theta);   figure(2); clf; hold on; axis equal; axis off;  % plot the surface   H=surf(X, Y, Z); shading faceted;   % pick a color   mycolor=[184, 77, 66]/256; % pink brick   mycolor=[184, 224, 98]/256; % light green%   mycolor=[225, 168, 48]/256; % golden brown%   mycolor=[0, 66, 17]/256; % dark green%   mycolor=[225, 0, 84]/256; % pink   % set some propeties   set(H, 'FaceColor', mycolor, 'EdgeColor','none', 'FaceAlpha', 1);   set(H, 'SpecularColorReflectance', 0.1, 'DiffuseStrength', 0.8);   set(H, 'FaceLighting', 'phong', 'AmbientStrength', 0.3);   set(H, 'SpecularExponent', 108);   % viewing angle   view(0, 12);% add in a source of light   camlight (-50, 54); lighting phong;      % save as png  print('-dpng', '-r200', 'Surface_of_revolution_illustration.png');