What Is a Jungle Gym?

History

• The jungle gym is an American invention. The design was patented by Sebastian Hinton, a lawyer from Chicago, in 1920. Hinton's goal was to give children something on which to exercise both their bodies and their imaginations. Many baby boomers remember the jungle gym from their neighborhood public or school playground---a tall, slightly terrifying monster that demanded to be conquered.

The Original Design

• Hinton's original 1920 design used short metal pipes arranged to form cubes. Each cube was 25 inches a side. However, "This construction I have found somewhat expensive to produce, and laborious to erect; while therefore maintaining the general structure shown in said applications I have adopted a novel and exceedingly efficient method of its construction"---longer, and thus, fewer, pipes!
  His jungle gym was 8 cubes long, 5 cubes high and 4 cubes wide. The top layer was 6 cubes wide by 2 deep, allowing room for children to run around the top layer. It had the added benefit of "reducing the height from which a clear drop is permitted to 8 feet, 4 inches approximately---a safe height even for 3-year-olds."
  Larger pipes ran from the structure's corners down to the ground, to brace it.

Math on the Playground

• Hinton had in mind a game for children on the jungle gym. The jungle gym was a three-dimensional space. Hinton's game made physical the Cartesian coordinates that name points in space on three axes, x, y, and z. When a number was called, the children would climb on the bars to find the named coordinate.
  Seems like an odd game for a lawyer to invent, doesn't it? Not if you consider Hinton's ancestors, who included many mathematicians who contributed to higher-level algebra, including George Boole, remembered best for inventing Boolean algebra.

Jungle Gyms Today

• Besides climbing---an activity that gave the jungle gym its other common name, the monkey bars---jungle gyms can be swung from with the hands, dangled from, or even hung upside down from.
  Today's jungle gyms take a variety of shapes. Cubes still exist, of course, but also geodesic domes, Mobius strips, triangles and swirling lines that seem to have been drawn by Salvador Dali.
  In the end, though, shape doesn't matter; fun does.

A Playground Staple

• Although metal jungle gyms can still be found, today's emphasis on safety has led manufacturers to use of other materials, such as wood, plastic and even taught rope. Often called "climbing structures," today's jungle gyms often form the anchor of larger playsets that include slides and swings.
  As slides, swings and merry-go-rounds pass from the public playground because they are declared too dangerous, the jungle gym, once the mighty metal monster of the playground, remains.