First 4-D geometry study sheet:

fourth dimension: we're just getting started with this one. I expect you to be able to answer questions like:

How is the fourth dimension different than the third dimension? What could a fourth dimensional person do that's different? What could a fourth dimensional person see that's different?

How is the third dimension different than the second dimensions? What can you do and see that a 2-dimensional person couldn't?

What would a 1-dimensional universe be like? What could a 1-d person do?

Answers to these questions, and some more specific questions