kengr

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"Everybody" knows that if you start at the North Pole, you can walk a mile south, then walk a mile east, then walk a mile north and wind up back at your starting point.

So, now for the trick. Where *else* on earth can you do the same thing. :-)

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From:

alatefeline

I'm going to guess that it is some point in some kind of specific-distance-away triangular polygon relationship to the South Pole. Maybe? I thought about the different poles and the equator, and that's my best guess, but I'm not confident about it.

From:

kengr

You're on the right track.

Picture the south pole.

Now picture a circle centered on it that has a *circumference* of 1 mile (it'd have a radius of approximately 840 feet, 4 inches (5280/2pi). So for any point on that circle, walking a mile east would return you to your starting point.

So if you start at any point on a circle centered on the south pole but with a radius 1 mile bigger, walking one mile sourth would put you on the 1 mile circumference circle, at which point walking one mile east would get you back to where you started on the circle and one mile north would get you back to your starting point.

This also works with circles that have a circumference of 1/2 mile (you walk around twice), 1/3rd mile, etc.

it's easier to explain with drawings, but I trust you get the idea.

From:

alatefeline

Yep! I can see it. Thanks!!!

From:

kengr

The kids you work with are probably a bit young for the trick, but if not it might be fun to watch their little heads spin at the first question, much less the trickier version. :-)

Worse than the "where do you bury the survivors" trick.

From:

alatefeline

I'll try it on some of their older siblings sometime. ;)

From:

conuly

The South Pole. (Which is how I first heard it anyway, though without the "what color are the bears" punchline, natch.)

Edited Date: 2017-12-12 05:51 am (UTC)

From:

acelightning

If you're at the South Pole, you can't walk a mile south. You could perform the mirror-image of the maneuver in the puzzle by walking a mile north, but that's not the same thing.