.<<<<<<<<<<<<<<<<<<.
vXXXXXXXXXXXXXXXXXX^
vX.<<<<<<<<<<<<<<.X^
vXvXXXXXXXXXXXXXX^X^
vXvX.<<<<<<<<<<.X^X^
vXvXvXXXXXXXXXX^X^X^
vXvXvX.<<<<<<.X^X^X^
vXvXvXvXXXXXX^X^X^X^
vXvXvXvX.<<.X^X^X^X^
vXvXvXvXvXX^X^X^X^X^
vXvXvXvXvX$.X^X^X^X^
vXvXvXvXvXXXX^X^X^X^
vXvXvXvX.>>>>.X^X^X^
vXvXvXvXXXXXXXX^X^X^
vXvXvX.>>>>>>>>.X^X^
vXvXvXXXXXXXXXXXX^X^
vXvX.>>>>>>>>>>>>.X^
vXvXXXXXXXXXXXXXXXX^
vX.>>>>>>>>>>>>>>>>.
vXXXXXXXXXXXXXXXXXXX
1 20 N