peristaltic locomotion

The black exhaust Black is apparently a depressing color. The reason ought to be rich mixture. That is to say, the mixture of gas in cylinder component is at night normal level. The incomplete combustion gas inside the combustion chamber make the carbon particle exhausted with the waste gas. Failure probably will come from the following reason: The story shocked me more than usual because I know my friend is a fairly good martial artist. He is often dubbed as 'talented' by his colleagues and superiors. What's wrong with this story? In theory, he may have wasted the thief quickly while he clearly had no weapon with him. According to him, he didn't know what to do. He knew how he could subdue such assault but he just did not know how to handle it at that time.