  Lights Out! is a game played on a $5 \times 5$ grid of lights, or more
generally on a graph. Pressing lights on the grid allows the player to turn off
neighboring lights. The goal of the game is to start with a given initial
configuration of lit lights and reach a state where all lights are out. Two
conjectures posed in a recently published paper about Lights Out! on Cartesian
products of graphs are resolved.
