---| 12 |-----------------------------------------

20    -----------------------|
      |                      |
      |                      |
      |                      |
      |           *          |
      |         * * *        |
10    -       * * * * *      |
      |           *          |
      |           *          |
      |           *          |
      |           *          |
      |           *          |
0     ------------|----------|
     0           10         20
               Arrow