Riemann is a genius! Although I'd probably need good Math sense like Ken Tay to do the Math, but I guess appreciating it is enough. But I would never imagine what geometry in four dimensions could look like... well, even have a shape that can be retro-extrapolated back to three dimensions! Just goes to show that one doesn't need the wisdom of four dimensions to struggle around in the three dimensional world.
I kinda just thought of something: A three dimensional object casts a two dimensional shadow in a three dimensional world. It is then possible to cast a single-dimensional shadow in a three dimensional world if you use a two dimensional object. And if you cast a shadow using a single dimensional object, then you'd get a point shadow, one that has zero dimensions.
Now... if you cast a shadow using a four dimensional object, you must then be able to get a three dimensional shadow. I'd like to think of it as... how come... we can see certain things, certain people, and yet, they're not there.
After all, they're just a shadow of their former self. It's up to you to think about it.
I really think the amazing (yes Christine, for a lack of a better word... sigh) thing about Relativity is how it links science and religion together, and yet it provides a platform for you to explain some things religion and science could never explain. Philosophy, economics and social issues, are also described in the theory of relativity.
Don't believe me? Well, too bad lor. It's really an all encompassing subject.