Mario and Luigi were in a subway. Luigi was reading the Koopa Times newspaper, doing a crossword puzzle. He was obviously having trouble so he said to Mario, "Yo bro, can you help me on this one word?" Mario said, "Maybe, what do you need?" "A 4-letter word that ends in IT." Mario replied, "What's the clue?" Luigi said, "What is in a bird cage and what Mario is full of." Mario replied, "Oh! That's easy! Grit!" Luigi said, "Oh, thanks. Uh, do you have a pencil with an eraser?"