uses crt,graph;
const
     x=0;
     y=0;
     xv=100;
     xn=100;
     xv2=100;
     xn2=100;
var
   a,
   b,
   yv,
   yn,
   yv2,
   yn2:integer;
   c:char;
begin
a:=detect;
Initgraph(a,b,'');
repeat
Setcolor(2);
line(50,150,50,200);
line(75,225,125,225);
line(150,200,150,150);
line(100,225,100,300);
line(75,300,125,300);
line(50,200,75,225);
line(150,200,125,225);
line(75,300,50,325);
line(50,325,150,325);
line(150,325,125,300);
line(125,300,100,325);
setfillstyle(1,2);
floodfill(100,310,2);
setfillstyle(1,2);
floodfill(125,310,2);
yv:=100;
yn:=200;
yv2:=150;
yn2:=150;
repeat
setcolor(5);
line(xv,yv,x+50,y+150);
line(xv,yv,x+150,y+150);
line(xn,yn,x+50,y+150);
line(xn,yn,x+150,y+150);
line(xv2,yv2,x+50,y+150);
line(xv2,yv2,x+150,y+150);
line(xn2,yn2,x+50,y+150);
line(xn2,yn2,x+150,y+150);
delay(3000);
setcolor(0);
line(xv,yv,x+50,y+150);
line(xv,yv,x+150,y+150);
line(xn,yn,x+50,y+150);
line(xn,yn,x+150,y+150);
line(xv2,yv2,x+50,y+150);
line(xv2,yv2,x+150,y+150);
line(xn2,yn2,x+50,y+150);
line(xn2,yn2,x+150,y+150);
yv:=yv+1;
yn:=yn-1;
yn2:=yn2+1;
yv2:=yv2-1;
until  yn2=200;
until keypressed;
closegraph;
end.