PROC Seg(a, b) IS 
  PS.MoveTo(a); 
  PS.LineTo(b); 
  PS.Stroke() 
END;

UI PointTool(Seg);

PRED OnBoth(p, a, b, c, d) IS 
  (p, a) PARA (p, b) AND 
  (p, c) PARA (p, d) 
END;

UI PointTool(OnBoth);

PROC Cmd0() IS 
  IF 
    VAR 
      a ~ (96.03, 445.9), 
      b ~ (173.7, 486.6), 
      c ~ (232.4, 517.2), 
      d ~ (135.6, 306.6), 
      e ~ (245.6, 324.9), 
      f ~ (300.5, 334), 
      g ~ (154.9, 397.8), 
      h ~ (178.8, 400.6), 
      i ~ (240, 406.9) 
    IN 
      OnBoth(g, a, e, b, d) AND 
      OnBoth(h, a, f, c, d) AND 
      OnBoth(i, c, e, b, f) AND 
      (a, b) PARA (a, c) AND 
      (d, e) PARA (d, f) AND 
      (g, h) PARA (g, i) -> 
        Seg(a, e); 
        Seg(a, f); 
        Seg(b, d); 
        Seg(b, f); 
        Seg(c, e); 
        Seg(c, d) 
    END 
  FI 
END;