anti-stream (n.) - an advanced stream mapping technique. A mapper will use the timing panel to reverse time temporarily by making the bpm negative in the storyboard editor temporarily. When combined with a stream, the stream itself becomes antimatter on the screen and behaves strangely: antiflow becomes flow, and vice versa. What scientists have found is that players become disoriented and often fail the map as a result. It has been coined one of the hardest patterns to hit due to its manipulation of higher dimensions.