Puzzle of the Day

(Note: The last Puzzle of the Day for the 2019–20 school year will appear on Wednesday. Thanks to all my readers! I hope you've had fun!)

The following quote from Wikipedia describes the origins of which piece of playground equipment?

"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 three-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."

Check back tomorrow for the answer, a shoutout to all the solvers, and a new puzzle!

Previous puzzle:

Kolonie-Deutsch is a dialect of German spoken by a few hundred people in the Amana Colonies of Iowa, a group of villages that began as a religious commune.

The Amana villagers also speak English, giving their dialect some unique mashups of English and German words. What produce item do they call Piestengel, combining the English word "pie" with the German word for "stem"?

Answer:

A stem that goes into pie? That must be rhubarb!

Aiden actually knew someone from the Amana Colonies, who informed him of Piestengel's other use besides pie filling—the villagers ferment it to make rhubarb wine.

Cheers to solvers Aiden, Leo S., Maddy, and Dr. Yetman!