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Marble Run
I have so many plans. It would incorporate a Galton board, a Ranque-Hilsch marble vortex tube, and a compartment lined with pinball bouncers with a camera-and-servo Maxwell's Demon that separated the balls into fast and slow sides.
Title text: I have so many plans. It would incorporate a Galton board, a Ranque-Hilsch marble vortex tube, and a compartment lined with pinball bouncers with a camera-and-servo Maxwell's Demon that separated the balls into fast and slow sides.


Ambox notice.png This explanation may be incomplete or incorrect: Created by MAXWELL'S DEMON - Please change this comment when editing this page. Do NOT roll away this tag too soon.

A Rube Goldberg machine is a fancifully complex system (either real or imagined), which makes use of an overly elaborate chain of actions. The name comes from an American cartoonist who was one of those who became famous for depicting convoluted and outlandish processes for accomplishing simple tasks.

There's a long history of people building actual contraptions along these lines. Such devices are almost never intended for practical purposes, but exist entirely for entertainment, and as an exercise in building complex and carefully planned systems. This has become particularly common in the internet age, as videos of particularly interesting examples can gain popularity online. The most common category of these devices is probably the marble run (also known as a rolling ball sculpture), in which the goal of the system is to move one or more balls or marbles from the beginning of the device to the end in interesting ways. This contrasts to the domino run where motions are transfered by many intermediate pieces painstakingly arranged, although both aspects are commonly combined in such contrivances.

When Megan tries to show Cueball an example of such a video, he refuses, not because he lacks interest, but because of how he predicts it will impact him. Cueball (likely as a stand-in for Randall), has sufficiently strong interest in things like designing, building and engineering complexity that he's certain he will eventually adopt building such devices as a hobby, and that it will dominate his time and attention. Accordingly, he appears to be deliberately delaying his exposure to such devices so that he can continue to pursue other hobbies, with the assumption that he will eventually succumb to this one.

Megan responds that he knows where he's going, but is taking "a really interesting and circuitous path" to get there. This points out the irony that the very avoidance of building Rube Goldberg machines follows the same principle on which such machines work.

The title text mentions specific ideas Cueball plans to incorporate into such a device.

A Galton board is a device that distributes falling balls into a normal distribution. It is the inspiration behind pachinko-style games[citation needed].

A Ranque-Hilsch Vortex tube is a device for separating compressed gas into hot and cold streams. While such a device isn't directly applicable to marbles, one can imagine using the principle to separate a stream of marbles based on speed.

Maxwell's Demon is a thought experiment by James Clerk Maxwell which would violate the Second Law of Thermodynamics. Maxwell proposed that, if a container of air was separated by a divider, with a door that allowed only one molecule through at a time, and a theoretical "demon" were to control the door to sort high-energy atoms into one side and low energy atoms into the other, the two sides would develop a temperature difference with no energy input.

Cueball's version of this apparently involves a large number of marbles bouncing around inside a compartment, with an automated system to divert the fastest moving marbles into one side, and the slowest moving into the other.


Ambox notice.png This transcript is incomplete. Please help editing it! Thanks.
[Megan is walking towards Cueball and showing her phone. Cueball holds a hand to his face and looks away.]
Megan: Check out this cool video of a Rube Goldberg marble run.
Cueball: No! Not yet.
[Megan has lowered her phone. Cueball has his hand in a fist.]
Cueball: I've always known I'm doomed to eventually become one of those people who builds elaborate marble runs in their garage.
Cueball: I can feel the pull.
Cueball: So satisfying.
[Close-up on Cueball.]
Cueball: I just want to do as many other things as I can before I give in and disappear into that world.
[Megan and Cueball are walking.]
Megan: So you know where you're going to end up, but you're trying to take a really interesting and circuitous path to get there.
Cueball: Exactly. Bounce around, maybe go off a few jumps.

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