........+---+....
......./   /|....
......+---+ |....
....+-|   | +---+
.../  |   |/   /|
..+---+---+---+ |
..|  /   /|   | +
..| +---+ |   |/|
..+-|   | +---+ |
./  |   |/   /| +
+---+---+---+ |/.
|   |   |   | +..
|   |   |   |/...
+---+---+---+....