It's a description... how can you not know that?
QUOTE(Dictionary)
nook Pronunciation: (nook)
n.
1. A small corner, alcove, or recess, especially one in a large room.
2. A hidden or secluded spot.
QUOTE(Dictionary)
cran·ny Pronunciation: (kran'e)
n. pl. cran·nies
A small opening, as in a wall or rock face; a crevice.
Your terrain is too complex, you must simplify it so resolve the problem.