Could parts of a mainly 3D object be built into an extra dimension? The situation I'm thinking of is this:

Two machines fully enclosed inside separate metal spheres with a wire going out of one sphere into 4D space and then back into 3D space in the other sphere connecting the two machines without ever going through the spheres.

This is under the assumption that a 4D space exists around our 3D space.

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    $\begingroup$ I'm unsure if you understand what special dimensions refer to... There is no "4D space". You can't go from being in 3D space to 4D space. Either you exist in an environment with 4 dimensions or you don't. As for your question: Yes you can. $\endgroup$
    – AngelPray
    Jul 15, 2017 at 0:04

2 Answers 2


Yes you can. Here's a way to visualize the reason behind this being the case:

Say you have 2 rings surrounding two seperate machines. Could you connect the two machines using a wire? Of course you could. Since you have access to 3 dimensions and not just 2, the rings don't actually pose much of a problem at all. The machines are enclosed with 2 dimensional shapes (circles), you have access to 3 dimensions of space.

Now in your situation it's essentially identical except instead of the machines being enclosed by 2 dimensional shapes they're enclosed by 3 dimensional shapes (spheres). But since you have access to 4 dimensions they don't actually pose any problem.

If you were a 2 dimensional creature living in a flat world unaware that space was actually 3 dimensional and I told you to connect the two machines with wire without going through the circles you'd probably think it was impossible at first thought. But only because you wouldn't be aware of what I would be. You wouldn't be able to look at the flat world from above.


A mostly 3d machine could be built with an extra dimension if (and exactly if) your universe has the 4d topology you need to use to build it in the first place. Whether that topology exists in the first place is up to you.

There would be the question of "what happens when you move one of the spheres." Depending on how your 4d topology functions, you may find it hard to keep the wire intact.


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