figure(1)
colormap([1 1 1])
ezsurf('(2+cos(v))*cos(u)','(2+cos(v))*sin(u)','sin(v)')
axis equal tight
 
 
figure(2)
colormap([1 1 1])
ezsurf('(cos(v))*cos(u)','(cos(v))*sin(u)','sin(v)')
axis equal tight

figure(3)
ezsurf('real(atan(x+i*y))',[-5,5,-5,5])






