IMPORT PS, Math, Anim;

CONST Duration = 2;

PROC Mess(a, b, c, d) IS 
  IF 
    PS.SetWidth(5); 
    Curve(a, b, c, d); 
    Curve(d, b, c, a); 
    Curve(a, b, d, c); 
    Curve(c, a, b, d); 
    Curve(d, c, a, b); 
    Curve(b, d, a, c); 
    Curve(c, d, a, b); 
    Curve(b, d, c, a); 
    Line(a, b); 
    Line(b, d); 
    Line(d, c); 
    Line(c, a); 
    Line(a, d) 
  FI 
END;

PROC Line(a, b) IS 
  PS.MoveTo(a); 
  PS.LineTo(b); 
  PS.Stroke() 
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 Curve(a, b, c, d) IS 
  IF 
    PS.MoveTo(a); 
    PS.CurveTo(b, c, d); 
    PS.Stroke() 
  FI 
END;

UI PointTool(Curve);

PROC Cmd0() IS 
  IF 
    VAR 
      a = (59.83, 438.4), 
      b = (222.7, 439.9), 
      c = (59.08, 256.4), 
      d = (234.8, 241.2), 
      e = (241.6, 188.1) 
    IN 
      Go(a, b, c, d, e); PS.Reset() 
    END 
  FI 
END;