program Dibujar;
uses Teclado, crt, Graph;

var
  Car: char;
  X, Y, Xant, Yant: integer;
  ErrCode,
  GrD, GrM: integer;

procedure Dib;
begin
{  PutPixel(X, Y, White);}
  SetColor((X div 3) mod GetMaxColor);
  Line(GetMaxX div 2, GetMaxY div 2, X, Y);
end;

begin
  GrD := VGA; GrM := VGAHi;
  InitGraph(GrD, GrM, '\tp7\bgi');
  ErrCode := GraphResult;
  if ErrCode <> GrOk then begin
    writeln('Hubo problemas: ', GraphErrorMsg(ErrCode));
    halt(1);
  end;
  X := GetMaxX div 2; Y := GetMaxY div 2;
  SetWriteMode(XORput);
  Dib;
  repeat
    Car := GetKey;
    Xant := X; Yant := Y;
    case Car of
      CsrArr: if Y > 0 then dec(y);
      CsrAba: if Y < GetMaxY then inc(y);
      CsrIzq: if X > 0 then dec(x);
      CsrDer: if X < GetMaxX then inc(x);
    end;
    Dib;
  until Car = chr(27);
  CloseGraph;
end.