Sport kites can also be great as a sort of demonstration of what a sail's crosswind potential could look like if it didn't have to lug around a vehicle, technic

Sport kites can also be great as a sort of demonstration of what a sail's crosswind potential could look like if it didn't have to lug around a vehicle, technically both downwind and upwind since they're essentially tracking a spherical concave shape centered directly downwind of the pilot. Speedkites in particular push the sail speed vs wind speed ratio to ridiculous limits. For scale, this kite is 190cm across. https://www.youtube.com/watch?v=_quR4xUSrZY https://www.youtube.com/watch?v=_quR4xUSrZY