%@DATE: 2 juin 2005
 
 input fichierps;
 
 InitFichierPS(-160,-160,160,160);
 
 u = 0.8cm;
 
 % la distance AB.
 l = 3;
 
 % Les points fixes.
 pair A,B;
 A = (0,0);
 B = (l,0) scaled u;
 
 % Les cercles.
 path cp, cq;
 cp = fullcircle scaled 4l scaled u;
 
 vardef Point(expr p) =
     draw p withpen pencircle scaled 4;
     draw p withpen pencircle scaled 3 withcolor white;
 enddef;
 
 for i=0 upto 100:
     beginfig(i);
 
 	FondImage((1,.89,.77));
 	draw cp withcolor 0.6white;
 		
 	pair P,Q;
 	
 	P = point (.08i) of cp;
 	Q = A reflectedabout(P,B);
 
 	if i=0:
 	    cq := Q;
 	else:
 	    cq := cq -- Q;
 	    drawarrow subpath(0,0.08i) of cp
 		withpen pencircle scaled 1;
 	    draw cq withcolor (0,.55,.27);
 	fi;
 	
 	
 	drawoptions(withpen pensquare scaled 2 withcolor (.7,.13,.13));	
 	draw A--P;
 	draw P--Q;
 	draw Q--B;
 	draw B--A;
 	drawoptions();
 		
 	Point(A);
 	Point(B);
 	Point(P);
 	Point(Q);    
     
     endfig;
 endfor;
 
 end