Don't imagine a grid. Instead imagine that "GO EAST" takes you onto a winding road. The road arcs southward and to go back you'd have to "GO NORTH". Further.

Don't imagine a grid. Instead imagine that "GO EAST" takes you onto a winding road. The road arcs southward and to go back you'd have to "GO NORTH". Further... some travels in Zork even drop you through a hole (though I forget if it tells you so). So going East might put you in the basement and there's no way to climb back up.