static JComponent gazelle_wavySpacer() {
  ret jMinWidth(30,
    dynamicallyPaintedComponent2((g, w, h) -> {
      var points = graphAsPolygon(x -> 1-sineSigmoid(x), w, h);
      //printVars(+w, +h, points := takeFirst(5, points));
      fillPrecisePolygon(g, points, gazelle_color1());
    }));
}