xxxxxxxx_______________+
xxxxxxx                |
xxxxxxx .            . |
xxxxxxx                |
xxxxxxx   xxxxxxxxxx   |
xxxxxxx   xxxxxxxxxx   |
xxxxxxx   xxxxxxxxxx   |
xxxxxxx   xxxxxxxxxx   |
xxxxxxx   xxxxxxxxxx   |
xxxxxxx   xxxxxxxxxx   |
 n                     |
 no     .            . |
 n                     x
