*   <li>{@code [3..6]} encloses {@code [4..4)} (even though the latter is empty)
   *   <li>{@code (3..6]} does not enclose {@code [3..6]}
   *   <li>{@code [4..5]} does not enclose {@code (3..6)} (even though it contains every value
   *       contained by the latter range)
   *   <li>{@code [3..6]} does not enclose {@code (1..1]} (even though it contains every value
   *       contained by the latter range)
   * </ul>
   *