This month’s puzzle comprised nine pictures, arranged in a grid. Irregularly placed letters along the edges of the grid spell out “tiling” and “partridge”. (And there are some extra tiles on the little side table on some of the photos too, what’s going on there.)

Each picture represents an incomplete “partridge tiling” of a 45-by-45 square. And those irregularly placed letters along the top and left edges? They become somewhat less irregular if you fill in the blank spaces along the boundary with the repeated alphabet string ABC….XYZABC…XYZABC…XYZABC…XYZABC…XYZABCDE.

And so: once you solve the nine grids, and find where the 1-by-1 squares – the “ones” – are located, you can extract a pair of letters (coordinates) for each of them. As an example, the “one” in the top-left picture is at the 19th row, 21st column, which we could map to (S, U). When we do this mapping for all nine grids, we get

(S, U) (M, O) (F, C) (U, B) (E, S) (I, S) (S, Q) (U, A) (R, E)

Now we just need to toss in those spare tiles on the side table in the first and seventh pictures, and we have our answer: “the sum of cubes is a square”, which is what the tilings prove :-)

P.S. Earlier this year we installed a large, custom-made tabletop version of this puzzle in our New York office. (And once 3025 rolls around perhaps we’ll make another one…)

Congrats to all the solvers able to decode the message!