%   mfile plotsharkfish
%   plot old iteration and current one side by side
    hold off, clf
%   get current locations of sharks (as complex numbers), and plot them
    sharkpnt = find(shark(2:d+1,2:d+1));
    sharkwhere = ZZ(sharkpnt);
    if length(sharkwhere) > 0,
       axis([0,d+1,0,d+1]), axis('square'), 
       plot(sharkwhere,'+k')
       title(['Current time step i= ',num2str(i)]) 
       hold on
    end
%   get current locations of fish (as complex numbers), and plot them
    fishpnt = find(fish(2:d+1,2:d+1));
    fishwhere = ZZ(fishpnt);
    if length(fishwhere) > 0, 
       plot(fishwhere,'or'), hold on
       axis([0,d+1,0,d+1]), axis('square'),
       title(['Current time step i= ',num2str(i)]) 
    end
    pause(.001)