A. 2s are never directly to the left or directly to the right of 4s.
B. Every column in which a 4 appears, at least one 4 has a 1 directly below it or directly above it (possibly both).
C. 4s are never directly to the left of 3s.
D. No number is directly above or directly below itself.
E. 1s can never be directly above or directly below a 3.