A mother-in-law disliked her son-in-law so much that she wanted to poison him. But the son-in-law was careful and always ate only what his mother-in-law ate. Over dinner one night, the mother-in-law cut a piece of meat in half, ate one half herself, and gave the other to her son-in-law. After that he died. How did she manage to do it?
She greased one side of the knife with poison.