  A de Bruijn arrays code is a set of $r \times s$ binary doubly-periodic
arrays such that each binary $n \times m$ matrix is contained exactly once as a
window in one of the arrays. Such a set of arrays can be viewed as a
two-dimensional generalization of a perfect factor in the de Bruijn graph.
Necessary conditions for the existence of such arrays are given. Several direct
constructions and recursive constructions for such arrays are given. A
framework for a theory of two-dimensional feedback shift register which is akin
to (one-dimensional) feedback shift registers is suggested.
