```[docs]def aaa():
# trick sphinx to build link in doc
pass

"""
Positions with - are empty.
Letters at row, col = (r, c) are connected
to letters with
(r+1, c),
(r-1, c),
(r, c+1),
(r, c-1).
"""

BRISTLECONE_GRID = \
r"""
-----AB-----
----ABCD----
---ABCDEF---
--ABCDEFGH--
-ABCDEFGHIJ-
ABCDEFGHIJKL
-CDEFGHIJKL-
--EFGHIJKL--
---GHIJKL---
----IJKL----
-----KL-----
"""

"""

>>> import cirq
(0, 5)....(0, 6)
(1, 4)...(1, 5)....(1, 6)....(1, 7)
(2, 3)...(2, 4)...(2, 5)....(2, 6)....(2, 7)...(2, 8)
(3, 2)...(3, 3)...(3, 4)...(3, 5)....(3, 6)....(3, 7)...(3, 8)...(3, 9)
(4, 1)...(4, 2)...(4, 3)...(4, 4)...(4, 5)....(4, 6)....(4, 7)...(4, 8)...(4, 9)...(4, 10)
(5, 0)...(5, 1)...(5, 2)...(5, 3)...(5, 4)...(5, 5)....(5, 6)....(5, 7)...(5, 8)...(5, 9)...(5, 10)...(5, 11)
(6, 1)...(6, 2)...(6, 3)...(6, 4)...(6, 5)....(6, 6)....(6, 7)...(6, 8)...(6, 9)...(6, 10)
(7, 2)...(7, 3)...(7, 4)...(7, 5)....(7, 6)....(7, 7)...(7, 8)...(7, 9)
(8, 3)...(8, 4)...(8, 5)....(8, 6)....(8, 7)...(8, 8)
(9, 4)...(9, 5)....(9, 6)....(9, 7)
(10, 5)...(10, 6)

"""
```