Controllable slope soaring

Controllable-slope soaring (also known as Walkalong gliding) is a type of slope soaring where a slope is made to follow a walkalong glider (a lightweight toy aircraft), both sustaining and controlling the glider's trajectory by modifying the wind in the vicinity of the airplane. A controllable slope is any object which can be used to affect the air under the airplane: a piece of cardboard, the pilot's hands or even head.

Source: Wikipedia — Controllable slope soaring (CC BY-SA 4.0)