The logical AND function operates on a 3-byte array, where all three bytes are Booleans, values restricted to 0 and 1. It ANDs the first and second bytes together, and it puts the result in the third byte:

f( [ A, B, X ] ) = [ A, B, C ], where A,B,C ∈ { 0, 1 }

C = AB

A and B pass through unchanged, while X is discarded.

Since A and B are Booleans, only their lowest bits are ANDed together:

In the Tetris realization below, the AND gate is miniscule in comparison to the swap circuits required for A0 to traverse the B lines.