Swinging on a swingset was patented (on a lark: https://www.newscientist.com/article/dn2178-boy-takes-swing-...) in 2000.
https://patents.google.com/patent/US6368227B1/en
Swinging on a swingset was patented (on a lark: https://www.newscientist.com/article/dn2178-boy-takes-swing-...) in 2000.
https://patents.google.com/patent/US6368227B1/en