1/15    In the same vein as the "hear hear" discussion below, is it
        "no shit" or "know shit?"
        \_ no shit, sherlock.
        \_ I believe this term had the inflection of a sarcastic "no shit?",
           in its original form. E.g. Bob: "It's raining" Joe: "No shit?"
           As in, "not telling me shit?" "not shitting me?". Over time it's
           become acceptable as a declarative "no shit", without the need for
           the sarcasm, meaning "duh, I already knew that dumbass" (or sherlock,
           which retains the sarcastic edge).