n=2*pi;
 
d=n/50+0.001;
 
[x,y] = meshgrid(-n:d:n,-n:d:n);
 
         nn=30
         j=0;
 
          M = moviein(nn);
          for j=1:nn
 
z=(x./sqrt(x.^2+y.^2)).^2.*(...
 -sin(sqrt(x.^2+y.^2)-j*2*pi/nn)...
 -cos(sqrt(x.^2+y.^2)-j*2*pi/nn)./sqrt(x.^2+y.^2)...
 );
 
v=[-1 -0.9 -0.8 -0.75 -0.5 -0.25 -0.1 -0.05 0 0.05 0.1 0.25 0.5 ...
0.75 0.8 0.9 1];

%v=[ -0.75 -0.5 -0.25 0 0.25 0.5 0.75 ];
 
contour(z,v);
%contour(z,30);
%colorbar
axis equal
%grid on
 
         M(:,j) = getframe;
         end
         movie(M,100,10)         
