uses crt,graph;
var gd,gm,i,x,y,x0,y0:integer;
c:char;
begin
gd:=0;
initgraph(gd,gm,'');
x:=20;
y:=240;
line(0,y+3,340,y+3);
line(340,y+3,620,410);
line(620,410,640,410);
setlinestyle(1,0,3);
repeat
if x<=340 then x:=x+5
else
begin
x:=x+5;
y:=y+3;
end;
setcolor(12);
circle(x,y,1);
delay(100);
setcolor(0);
circle(x,y,1);
until (x>620)or(y>460);
setcolor(12);
circle(x,y,1);
readln
end.