Animacja

uses crt,graph;
const r0 = 20;
var s, t: integer;
    xm, ym, xp, yp: integer;
    x: integer;

procedure wlaczgrafike;
begin
  initgraph(s,t,'');
  xm:=getmaxx; xp:=xm div 2;
  ym:=getmaxy; yp:=ym div 2;
end;

procedure kolo(xx,yy,rr,kk:integer);
begin
  setcolor(kk);
  circle(xx,yy,rr);
  putpixel(xx,yy,kk);
end;

begin
  wlaczgrafike;
  for x:= 0 to xm do
  begin
    kolo(x,yp,r0,yellow);
    delay(10);
    kolo(x,yp,r0,black);
  end;
  readkey;
  closegraph
end.