%   mfile plotfish
%   plot old iteration and current one side by side
%   build coordinate grid (of positions as complex numbers)
    [XX,YY]=meshgrid(1:d,1:d);
    ZZ=XX+sqrt(-1)*YY;
%   get current locations of fish (as complex numbers)
    fishpnt = find(fish(2:d+1,2:d+1));
    fishwhere = ZZ(fishpnt);
%   make plot of (current) fish positions
    hold off, clf
%   subplot(121)
    plot(fishwhere,'ok'), grid, 
    axis([0,d+1,0,d+1]), axis('square'),
    title(['Current time step i= ',num2str(i)]) 
%   get old locations of fish (as complex numbers)
%   fishpnt = find(oldfish(2:d+1,2:d+1));
%   fishwhere = ZZ(fishpnt);
%   make plot of (old) fish positions
%   subplot(122)
%   axis([0,d+1,0,d+1]), axis('square')
%   title(['Last time step i-1= ',num2str(i-1)]) 
%   plot(fishwhere,'ok'), grid, 
    pause(.5)