Symmetric X Error Bars
Y values
+--------------------------------------------------------------------------------+
| 3                                                                              |
| |                                                                              |
| |                                                                              |
| |                 -- -- -                             --- Data with X errors   |
| |            - --        - --                                                  |
| 2         ----               -                                                 |
| |        -                     --                                              |
| |       -                        -                                             |
| |     --                         ----                                          |
| |  -- -                             -                                          |
| 1                                    -                                         |
| |                                      -                                       |
| |                                       -                                      |
| |                                       ----                                   |
| 0                                          -                                   |
| |                                           -                                  |
| |                                            -                                 |
| |                                             -                                |
| |                                              -                               |
| -1                                              -- -                           |
| |                                                 -                            |
| |                                                  -                           |
| |                                                   --                         |
| -2                                                    -                        |
| |                                                       -                      |
| |                                                      - --                    |
| |                                                           --                 |
| |                                                              -- -- -- --     |
| +-----------+--------------+--------------+--------------+--------------+----- |
| -3          2              4              6              8             10      |
+--------------------------------------------------------------------------------+
                                    X values