  Bingo is played on a $5\times 5$ grid. Take the 25 squares to be the ground
set of a closure system in which square $s$ is dependent on a set $S$ of
squares iff $s$ completes a line - a row, column, or diagonal - with squares
that are already in $S$. The closure of a set $S$ is obtained via an iterative
process in which, at each stage, the squares dependent upon the current state
are added. In this paper we establish for the $n \times n$ Bingo board the
maximum number of steps required in this closure process.
