@NotNull
  private static Path2D makeCurvePath(int x1, int x2,
                                      int y11, int y12, int y21, int y22) {
    Path2D path = new Path2D.Double();
    path.append(makeCurve(x1, x2, y11, y12, true), true);
    path.append(makeCurve(x1, x2, y21, y22, false), true);
    path.closePath();
    return path;
  }
@NotNull
  private static Path2D makeCurvePath(int x1, int x2,
                                      int y11, int y12, int y21, int y22)