NIC> (split-by-level *k*)
((((0 0 -1) ((BAR) (BAR) (BAR) (BAR) (BAR) (BAR) (BAR)))
((0 1 -1) ((BAR) (BAR) (BAR) (BAR) (BAR) (BAR) (BAR)))
((0 2 -1) ((BAR) (BAR) (BAR) (BAR) (BAR) (BAR) (BAR)))
((0 3 -1) ((BAR) (BAR) (BAR) (BAR) (BAR) (BAR) (BAR)))
((0 4 -1) ((BAR) (BAR) (BAR) (BAR) (BAR) (BAR) (BAR)))
((0 5 -1) ((BAR) (BAR) (BAR) (BAR) (BAR) (BAR) (BAR))))
(((0 0 0) ((BAR) (BAR) (BAR) (BAR) (BAR) (BAR) (BAR)))
((0 1 0) ((BAR) (FOO) (FOO) (FOO) (FOO) (FOO) (BAR)))
((0 2 0) ((BAR) (FOO) (FOO) (FOO) (FOO) (FOO) (BAR)))
((0 3 0) ((BAR) (FOO) (FOO) (FOO) (FOO) (FOO) (BAR)))
((0 4 0) ((BAR) (FOO) (FOO) (FOO) (FOO) (FOO) (BAR)))
((0 5 0) ((BAR) (BAR) (BAR) (BAR) (BAR) (BAR) (BAR))))
(((0 0 1) ((BAR) (BAR) (BAR) (BAR) (BAR) (BAR) (BAR)))
((0 1 1) ((BAR) (BAR) (BAR) (BAR) (BAR) (BAR) (BAR)))
((0 2 1) ((BAR) (BAR) (BAR) (BAR) (BAR) (BAR) (BAR)))
((0 3 1) ((BAR) (BAR) (BAR) (BAR) (BAR) (BAR) (BAR)))
((0 4 1) ((BAR) (BAR) (BAR) (BAR) (BAR) (BAR) (BAR)))
((0 5 1) ((BAR) (BAR) (BAR) (BAR) (BAR) (BAR) (BAR)))))
NIC>