"Walking" around a fulcrum...

[iacob alex]

..... is a metaphor related to a continuous rotating mass-spring system with a central support/fulcrum.
Let's start with the human inverted pendulum ( mechanical equivalent...) , walking on a horizontal surface , at :
      https://vimeo.com/34891251
      https://bio.biologists.org/content/8/6/bio043695?rss=1
.....then skating on a half-pipe ( concave surface ) , at :
      https://nickdrachman.wordpress.com/2020/03/26/the-physics-of-vert-skating/
      https://mpora.com/skateboarding/half-pipe-physics-science-skateparks/
.....an a possible full rotating ( not swinging...) mass-spring system , as :
      https://youtu.be/z6_NRNw88Jw
      but this time , as a "self" motion/spinning arm , due to gravity free fall and rotational inertia ( "pumping" spring )!?
      The essence is the sliding mass and the "working" spring...or inertia "assisted" gravity.
      Al_ex

[iacob alex]

.....if we start with a lot of theory (how to pump a swing...) ,at :
     http://audiophile.tam.cornell.edu/randpdf/swing.pdf
.....but we play it with :
     https://youtu.be/z6_NRNw88Jw
.....initiated at the horizontal line.
     Have we a self-accelerated "game" (lab-demo) ? !
     Nothing more then a minor "substitution" : the human actor ( elastic "body"...) with a spring-sliding mass ( variable pendulum)...or a "minimized robot".

     All the Best! / Al_ex