The downvotes are, I assume, from the *WHOOSH* sound as the point flies over your head.

This is the optional packing of 17 squares in a minimum-size larger square. Of course it’s not optional everywhere. It’s specific to 17 squares packed in a square.

The joke is that there’s no reason to choose 17 squares as, clearly, a rectangular* array is optimal.

*squares are, of course, rectangles.