This is a simple technique using the outer parallel of a Median Line set to project a minor swing expanding into a major swing. Basically, small swings growing up to be a major swing. This chart of the GBP/USD 45 minute is a progression from a previous post (The Process Of a Median Line Set and 3 Basic types of Trades).
Small swings grow into bigger swings, especially when coming off a top or bottom. This expanding swing tends and confuse both longs and shorts and clean the book so to speak.
When the minor swing breaks, this tends to stop out the traders who were chasing longs. At the same time, the traders with a short bias get encouraged to sell. An Andrews Median Line set placed on the minor swing is a way to project this expansion into a major swing.
What happens is that traders are pushing the small swings (Process of a Median Line and 3 Types of Trades) and the last swing is getting washed. I will include the process of a Wash & Rinse in the video.