A man came to visit at a convent while the superior mother was out of town. He left before she returned, and was careful to leave nothing behind. The nuns said nothing about his visit, so how did the superior mother figure out that a man had been there?
If a blue house is made out of blue bricks, a yellow house is made out of yellow bricks and a pink house is made out of pink bricks, what is a green house made of?
