static JComponent gazelle_wavySpacer() {
  ret jMinWidth(30, swing(-> new JComponent {
    public void paintComponent(Graphics g) {
      int w = getWidth(), h = getHeight();
  
      var points = graphAsPolygon(x -> 1-sineSigmoid(x), w, h);
      //printVars(+w, +h, points := takeFirst(5, points));
      fillPrecisePolygon(g, points, gazelle_color1());
    }
  }));
}