CONST Duration = 2;

PROC Mess(a, b, c, d) IS 
  IF 
    PS.MoveTo(a); 
    PS.CurveTo(b, c, d); 
    PS.CurveTo(b, c, a); 
    PS.CurveTo(b, d, c); 
    PS.CurveTo(a, b, d); 
    PS.CurveTo(c, a, b); 
    PS.CurveTo(d, a, c); 
    PS.CurveTo(d, a, b); 
    PS.CurveTo(d, c, a); 
    PS.LineTo(b); 
    PS.LineTo(d); 
    PS.LineTo(c); 
    PS.LineTo(a); 
    PS.LineTo(d); 
    PS.SetWidth(5); 
    PS.Stroke() 
  FI 
END;

PROC PatT(a, b, c, d, e, t) IS 
  VAR 
    theta = 2 * Math.Pi * t, 
    p = (COS(theta), SIN(theta)) 
  IN 
    Mess(a, b, c, p REL (e, d)) 
  END 
END;

PROC Go(a, b, c, d, e) IS 
  Anim.Play((CLOSE(PatT, a, b, c, d, e), 
             Duration)) 
END;

UI PointTool(Go);

PROC Cmd0() IS 
  IF 
    VAR 
      a = (57.56, 469.5), 
      b = (261.3, 411.1), 
      c = (28.78, 294.3), 
      d = (259, 251.1), 
      e = (181.8, 165.4) 
    IN 
      Go(a, b, c, d, e); PS.Reset() 
    END 
  FI 
END;