Lockheed ring wing airliner concept - GIF

[Toolmaker51]

When I was very young, I tried all manner of contours (in limited facilities of ~10 yo) to compress air through 'funnels' and create propulsion on paper airplane test-beds, kite shapes, later on rubber-band powered, being lightest available. Abject failures, fun, logical, mind twisting failures.
However, developed good sketching, taking notes, measuring and timing skills, used countless times since. Took up actual flight classes, nailing ground school and simulator, then first gas crisis hit.
Goodbye flying!
Still not over it.