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### Can you solve this riddle?

Posted: Thu Sep 03, 2015 7:44 pm
A person named Alice is on one side of a river and manages to walk around it without using a bridge or stepping in the river and the river is far too big to jump across.

After getting around the river Alice grabs something made from a spongy material and glues it between two poles. She then grabs a sponge and puts it on top of the spongy material and the sponge falls through the spongy material without tearing the spongy material or teleporting to the other side.

One of Alice's friends is on the beach of a small island and Alice goes all the way around the beach of the island but she does not see her friend even though her friend and her never leave the beach and her friend does not move at all during the time she walks around the beach. The beach has no places to hide, the beach is well lit, the beach is extremely narrow, and Alice has perfect vision

The whether on the planet Alice lives on is extremely calm because every point on her planet moves around the center at the same rate. Her planet has an isoclinic rotation.

When Alice sees a string tied in a knot she is able to untie it by simply tugging on the string.

Alice has a difficult time standing on a tight sheet without falling off even when she on the middle of a 100m by 100m sheet and the sheet is strong enough not to break and rigid enough to not bend from her weight.

The question is what is special about the environment Alice lives in that allows all this to happen.

### Re: Can you solve this riddle?

Posted: Thu Sep 03, 2015 8:14 pm
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AlternateGravity wrote: When Alice sees a string tied in a knot she is able to untie it by simply tugging on the string.
It's 4D? (Or, of course, even higher-dimensional.)

The whether on the planet Alice lives on is extremely calm because every point on her planet moves around the center at the same rate. Her planet has an isoclinic rotation.
That's impossible in 3D space, but is possible (and IIRC the equilibrium) in 4D. Also if you google isoclinic rotation the answer almost jumps out at you.
Alice has a difficult time standing on a tight sheet without falling off even when she on the middle of a 100m by 100m sheet and the sheet is strong enough not to break and rigid enough to not bend from her weight.
I'm guessing this is because to Alice, the 100x100 sheet is as thin as a thread - it's missing a dimension. (Can you balance on a 100m by 1 cm string easily?)
One of Alice's friends is on the beach of a small island and Alice goes all the way around the beach of the island but she does not see her friend even though her friend and her never leave the beach and her friend does not move at all during the time she walks around the beach. The beach has no places to hide, the beach is well lit, the beach is extremely narrow, and Alice has perfect vision
For her, the beach is 2D, instead of our 1D* beaches. She could go around the beach [you could imagine it as a surface of a sphere] and not see her friend. (Remember, this is an island, not a lake.)

*mumble mumble curled up dimensions
Gravitons would be my favorite particle as their existence could prove extra dimensions.
"..."

At first, my leading theory was she lives on a (topologically, at least) torus. She can walk around the river, and walk "around" a beach without seeing it all (though I guess that would be two beaches instead). However, this doesn't fit with most other clues.

### Re: Can you solve this riddle?

Posted: Sun Sep 06, 2015 5:08 pm
You are correct. I wasn't sure if anyone would get the correct answer to this but you got the correct answer.