by alkaline » Fri Jan 02, 2004 4:53 pm
ok here's the deal with drawing things from higher dimensions. In planespace, if they use lines for their drawings, they can only see the front "face" of the object drawn. They don't know what the rear of the object is shaped like, because lines hide what is behind them. However, if they use points, they can show all the vertices of a shape. They can use darker colors for closer points and lighter colors for farther points, giving an impression of its shape. This is hard to do with circles - the more points you use, the more like a circle the shape looks, but the more complicated it is and the more points in the front hide the ones in the rear. The big problem with points though is that you can't show how they are connected to each other - They are just a random set of dots with it not being obvious how they are related.
Enter realmspace. We can draw points like bionians, but we can also draw lines that don't hide each other. Thus, we can show the connectedness of shapes. Circles are easy to depict. Spheres are difficult though - the more lines we draw to make a sphere, the more the rear of the sphere is covered by the lines in the front. But, the situation is better than in planespace - we can show more of the shape than bionians can of the circle. It's quite difficult to show the shape of a sphere with dots. When we use planes for drawing, it is like using lines in planespace - we only see the front of the shape.
Then there is tetraspace. They can draw with points, lines, and planes. When they draw with planes, the planes don't cover each other up, they only cross in linear intersections. The drawings of theirs that don't cover the rear of the object (using planes) look fuller to them than our drawings of shapes that don't cover the rear (using lines): their planar-surface drawings use 2 of 4 dimensions, verses our linear drawings which use 1 of 3. Tetronians can still draw in lines though, as we can draw in points - but lines are more useful to them than points are to us, because they give an overall shape (through their connectedness) instead of a set of random-looking points. Thus, tetronians can make useful drawings out of either lines or planes. They can make either line drawings or plane-drawings of glomes.
Our line drawings of 3-dimensional objects are distorted because of the projection onto a plane. They are not what the real shape is. Line drawings of tetronian shapes on tetronian paper are also distorted versions of the real tetronian shapes. Line drawings of tetronian shapes on planar paper are even more distorted, but you can still draw them. All of the hypercube applets on the internet show tesseracts projected onto a plane, thus showing that drawing these shapes is possible, even if they are hard to understand.
Bob can draw lines at various angles, and although the shape may not hint at a 4-dimensional shape to you, maybe to a tetronian used to dealing with distorted drawings of shapes within his own space, would recognize the shape. Thus, to the tetronian, Bob has drawn something that hinted at the fourth dimension.