I learned that from the Great Stan Lee. Not personally, of course, I'm name dropping via TV interview. He remembered getting a letter about the Fantastic Four...where a fan said it was supers smart of him to symbolically tie each member's powers with the four basic elements, Air (Sue's powers were unseen but strong), Earth (Thing's rocky hide), Fire (Torch, obviously), and Water (Reed's stretching could be considered liquid like) without being blatant. Stan admitted, his response was "Well, that makes me sound smart and he wrote back "Glad you caught that!"" 🙂
