function [B] = DrawRings(A,DA,DB,CA,CB,xc,yc,Nrings)
B=A;
[My,Nx]=size(B);
    for m1=1:Nrings;
        m=1+Nrings-m1;
       % outside diameter
       for dx=1:DB(m)
       for dy=1:DB(m)
           x=(dx-1)+xc-(DB(m)-1)/2;
           y=(dy-1)+yc-(DB(m)-1)/2;
           if x>=1
               if x<=Nx
                   if y>=1
                       if y<=My
                           %
                           B(y,x)=CB(m);
                           %
                       end;
                   end;
               end;
           end;
       end;
       end;
       % inside diameter
       for dx=1:DA(m)
       for dy=1:DA(m)
           x=(dx-1)+xc-(DA(m)-1)/2;
           y=(dy-1)+yc-(DA(m)-1)/2;
           if x>=1
               if x<=Nx
                   if y>=1
                       if y<=My
                           %
                           B(y,x)=CA(m);
                           %
                       end;
                   end;
               end;
           end;
       end;
       end;
    end; % m
end