Tova rushed into her parents' room. "What's wrong, Papa?"
"Let me ask you a question," said Shlomo. "Why does a cow give milk?"
"Everyone knows that, Papa. A cow gives milk because she eats grass."
Shlomo and Rivka beamed at their youngest daughter.
"What a wise child you are," said Shlomo. "So if we feed grass to our hens, they will still lay eggs, but they will also give us milk."
"Shlomo," said Rivka, "you are a genius."
"I am indeed," said Shlomo, and he blushed.