function Polygons(a0,b0,radius,n)
%
%
% displaying a polygon.
%

delata_radius=radius/n;
radius_local=0; 
% the external radius of a polygon 
% i.e. the radius of a circle that
% encloses the polygon.
for j=1:n
    % radius_local=radius_local+delata_radius;
    % radius_local=radius/j;
    radius_local=j*delata_radius;
    n_sides=j+2; % number of sides of the polygon.
    % Display one polygon with n_sides,
    Polygon(a0,b0,radius_local,n_sides);
end % j