CONST Duration = 2;

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

UI PointTool(D);

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

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

UI PointTool(Go);

PROC Cmd0() IS 
  IF 
    VAR 
      a = (78.01, 402), 
      b = (229.5, 395.9), 
      c = (207.5, 231.3), 
      d = (81.8, 194.2), 
      e = (259.8, 191.1) 
    IN 
      Go(a, b, c, d, e); PS.Reset() 
    END 
  FI 
END;