Thinking about school time of yesteryear. Memories of our jungle gym, 12-foot high slide, merry-go-round, and swing set. On grass? On woodchips? Ha! On asphalt and concrete slabs, baby! Teachers would come running, "No no no!" as we would swing higher and higher, launching ourselves off into space in glorious parabolic arcs that would have made Robert Goddard proud. Nothing shattered, nothing broke. Our bones were made strong by milk, fluoridated water, and the American Dream. In my four short years on the playground, the only injury we had was a kid who fell like a Plinko chip from the top of the jungle gym, richocheting off the steel bars as he descended through the center of the steel lattice. He hurt his elbow.

The Jungle Gym
>The first jungle gym was invented in 1920 and patented by lawyer Sebastian Hinton, in Chicago. It was sold under the trademarked name Junglegym. The term "monkey bars" appears at least as far back as the 1930s though Hinton's initial patent of 1920 appeals to the "monkey instinct" in claiming the benefits of climbing as exercise and play for children, and his improvement patents later that year refer to monkeys shaking the bars of a cage, children swinging on a "monkey runway", and the game of "monkey tag".

Jungle? Monkey instinct?! THAT'S RACIS-

>Hinton's father, mathematician Charles Hinton, had built a similar structure from bamboo when Sebastian Hinton was a child; his father's goal was to enable children to achieve an intuitive understanding of 3-dimensional space through a game in which numbers for the x, y, and z axes were called out, and each child tried to be the first to grasp the indicated junction. Thus, the abstraction of Cartesian coordinates could be grasped as a name of a tangible point in space.

Oh! Never mind.

Pic related: Hinton's second prototype jungle gym is still standing at Crow Island School in Winnetka, Illinois.