+-+--------------------------+------------------------+------+--------+
  | |http://www.mecad.org/net_condition/referencias/simbo.html |        |
  +-+--------------------------+------------------------+------+--------+
  | |           |              |                        |      |        |
  | |           |              |                        |      |        |
  | |           |              +                        +      +--------+
  | |           |              |                        |      |        |
  | |           |              |                        |      |        |
  | |           +              +                        |      |        |
  | |           |              |                        |      |        |
  | |           |              |                        |      |        |
  | |           |              |                        |      |        |
  | |           +---+-+----+---+-----------------------++--+---+        +
  | |           |     |    |   |                       |   |   |        |
  | |           |     |    |   |                       |   |   |        |
  | |           |     |    |   |                       |   |   |        |
  | |           |     |    |   |                       |   |   |        |
  | |           |     |    |   |                       |   |   |        |
  | |           |     |    |   |                       |   |   |        |
  | |           |     |    |   |                       |   |   |        |
  | |           |     |    |   |                       |   |   |        +
  | |           +-----+----+--++-----------------------+---+---+        |
  +-+-----------+             |                                |        |
  |             |             |                                +        |
  |             |             |                                |        |
  |             |             |                                |        |
  |             |             |                                |        |
  +-------------+-------------++-------------------------------+----+-+-+