WTF Fun Fact 13246 – The Mathematical Roots of the Jungle Gym

A Princeton University mathematician named Sebastian Hinton invented the jungle gym (and monkey bars). He patented them as the “jungle gym” in 1920. Hinton designed the apparatus as a way to help children develop physical coordination and endurance – and to understand theoretical geometry.

What’s the history behind the jungle gym?

According to Smithsonian Magazine (cited below): Hinton “built a cubic bamboo grid in the family’s backyard to teach [his children] to visualize space in three dimensions as they moved through the structure. But the kids were more drawn to climbing and swinging on the bars.”

Cimbing is a near-universal juvenile activity in humans and other primates. However, the safety of jungle gyms and monkey bars has come into question. Still, child psychologists insist that “risky play” is essential on some level for healthy development.

Hinton’s patent document describes a “climbing structure.” It consists of a series of metal bars arranged in a vertical or diagonal configuration supported by a frame. The bars are spaced apart at a distance requiring the user to stretch and grasp the next bar to continue.

The document includes detailed illustrations and specifications for the construction and installation of the climbing structure.

Playground mathematics

Hinton’s math background played a complex role in the creation of the equipment.

Living in Japan at the time, Hinton built the bamboo framework in his backyard for his children. One of his goals was to get kids moving in three-dimensional space. Without this experience, he didn’t think humans could properly grasp the mathematical concept of a fourth dimension. The fourth dimension can be used to help explain the geometry and topology of three-dimensional objects.

For example, a jungle gym can be thought of as a set of interconnected vertices, edges, and faces that define its shape and structure. This idea is related to the concept of a “graph” in mathematics, which is a set of vertices that are connected by edges.

In some cases, the topology of a three-dimensional object can also be related to a four-dimensional object. For example, a hypercube or tesseract is an extension of the three-dimensional cube into a fourth dimension.

While this is a highly abstract concept, Hinton designed the jungle gym/monkey bars with this in mind.

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