Video of cube passing through hole in equally sized cube

Insert why_not_both.gif

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Pudel is German for poodle. It could be that an English speaker misinterpreted it as puddle. Maybe poodle, puddle, and Pudel were all spelled the same way because back then, spelling was a suggestion at best.

You can’t prove that a dog can’t shapeshift, only that it’s not currently shapeshifting. Maybe it can but doesn’t want to :wink:

You can prove that a dog isn’t bulletproof simply by shooting it.

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What? I mean, it’s not like it’s a cat. Sheesh. :slight_smile:

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Today I learned to step-up my phone pranking from, “Do you have Prince Albert in a can?” to “Do you have Prince Rupert in a cube?”

Put the sophistication back in sophomoricism!

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I disagree. How often do you transport a cubical box through another one the same size while moving furniture? (It might feel intuitively clear, like flatness of the Earth or the fact that heavier objects fall faster than lighter ones…)

The equivalent question is, is there a projection of the cube along some axis so that the shadow contains a square that does not touch the edge of the shadow. That is not obvious. It isn’t tremendously difficult to show using Cartesian coordinates, but keep in mind these were invented during Rupert’s lifetime; while his big sister Elizabeth, Princess of Bohemia was a penpal of Descartes, I don’t know how fluent Rupert was in the technology.

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On the internet, nobody knows that you are a shapeshifting dog.

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stil tru

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defiantly

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Ah, reminds me of the prank calls of my youth…

C: Do you have Prince Rupert in a cube?
PDD: Why yes I do.
C: Then let him pass through. [click]
C:

edit: missed @cntrfldr’s post above…

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I think my surprise is this: Would it be possible to cut a hole in one sphere, so that another sphere of the same size could pass through?

No, no way. The only way a sphere could pass through another sphere of the same size would be if the hole were exactly as big as the sphere, so you wouldn’t have any original sphere left.

So at first blush it seemed surprising that a cube could have a hole in it big enough for another cube of the same size – and even a little bigger! – to pass through. But then you realize that this is because, at specific angles, you could draw a square in a cube’s silhouette that is larger than any one of its sides.

When put like that, it doesn’t seem so surprising, but I think that speaks to our assumptions when first picturing the problem.

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To follow in this vein, it also serves to illustrate why manhole covers are generally round rather than square, rectangular, or oblong. With very simple fabrication effort, a circular manhole cover can be made so as not to be able to pass/fall through the opening it’s intended to cap.

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This is true for any curve of constant diameter, a class of convex shapes that is broader than circles. Some such curves have been used to make drill bits that drill square holes.

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This is the same Prince Rupert that invented the Mic Drops, right?

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I remember when I was a pre-teen I used to call up the local tobacconist and ask “Do you have Prince Rupert in a can that can pass through a can of equal size, just sideways?” And the tobbaconist would say “Yes, of course” and then I would say “Then let him out!” and I would laugh, and laugh, and laugh…

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OK, that’s all folks…

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Go ahead. It’s okay. We know you want to…
We of the Rupertian “comedy” collective allow all sorts into our fold (even Ruprechts)

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Reuleaux triangle:

Drill bit:

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