What is the driving-point resistance across the diagonal of a square face-or more generally, between any two nodes-of a uniform infinite square grid of 1-[2 resistances? This puzzle has been cropping up in the electrical engineering literature for many decades and reappeared in two recent issues of IEEE Circuits and Systems Magazine. Described herein is an analysis that completely resolves the matter. In fact, it does so for the general case of an n-dimensional resistive grid whose resistors are all the same, or perhaps vary in one direction only.