What did the Prophet Muhammad (saw) do when `Abdullah brought him two stones and a dried piece of dung?
 Narrated `Abdullah:                     The Prophet went out to answer the call of nature and asked me to bring three stones. I found two stones and searched for the third but could not find it. So took a dried piece of dung and brought it to him. He took the two stones and threw away the dung and said, "This is a filthy thing."