Module
The player's pointer gestures: a single tap toggles playback with a mouse and brings the control bar in or out with a finger, a double tap in the middle toggles fullscreen, a double tap on an edge starts a seek run — where every further tap on that edge adds a step and an indicator counts them — and a press held on the frame runs the lesson at double speed until it is released. All of them are the YouTube app's conventions, which the learner's thumbs already know.
The class that marks a gesture as one of the two edge regions.