Continuing yesterday’s thought … if you were looking at a 4D object in front of you — holographically, the way Tera presented it to Trey — how would you rotate it, to see it from different points of view?
First let’s look at how people rotate 3D things on computers. One common way uses something called a “virtual trackball”. It’s basically just an image of a trackball, seen from above. When you drag your finger over the image, it does what a real trackball would do.
As you can see in the above image, a virtual trackball “rotates” around the vertical axis when you drag left and right (the red arrow), about the horizontal axis when you drag up and down (the green arrow), and about the axis that comes toward you when you spin around its edge (the blue arrow).
So here we have an example of a completely two dimensional thing that lets you rotate stuff in 3D. Perhaps we can do something similar for rotating stuff in 4D…