
            |  * *                          
            |  * * * *                      
            |    * *   * *                  
            |    *   *     * *              
          5 -      *   *       * *          
            |      *     *         * *      
            |        *     *           * *  
            |        *       *             *
            |          *       *            
         10 -          *         *          
            |            *         *        
            |            *           *      
            |              *           *    
            |              *             *  
         15 -                *             *
            |----------|---------|---------|
                       5        10        15