The images show five out of six views of a regular octagon (as clued by the bottom, which reads, "This is the bottom of a 3d cross polytope"). The remaining view, when reconstructed, spells "OF AFFAIRS THAT ARE STRICTLY PLATONIC / BUT [ANSWER] ARE ETC". Combined with the "I've heard..." at the top, this forms part of the lyrics of Diamonds are a Girl's Best Friend, and the word replaced by "[ANSWER]" is DIAMONDS.
