"He keeps up this Superman act until the teapot lid starts to slow down."

Superman logo
Creative Commons AttributionSuperman logo - Credit: udannlin
The boy on the teapot lid (playground roundabout) is imitating Superman, one of the cultural icons for several generations, starting in 1938 with his first appearance in DC comics and subsequently appearing not only in comic form, but on TV, films and latterly video games. His almost invincible superhero status (contrasting with the meek manners of Clark Kent, his secret persona) and especially his ability to fly, made him irresistible. For a generation that grew up in the 1970s and 1980s it was Christopher Reeve's portrayal on film that defined Superman, but in the 50s, at least for American audiences, it was the more portly and somewhat older figure of another Reeves, George, who brought him more stiffly to life in  a TV series that ran for 104 episodes from 1952-1958, sponsored by cereal maker Kellogs.

Here is the intro to the 1950s TV version.