Curl

a straight swipe flies straight. bend yours.

pull the ball back and let go -- spin bends the flight around the wall

Pull back from the ball and release, like a sling. How far you pull sets the pace; how far ACROSS you pull sets the spin. Spin is not a one-off kick sideways -- it pushes the ball the same way on every frame it is in the air, so the longer the flight, the further the path bends. That is why the ball can leave to the left of the wall and still finish inside the right-hand post. The dim second ball is the control: identical boot, no spin. Watch where it ends up.

Concepts: spin, trajectory.

An interactive you play with one thumb, on Wundr.