We're all used to graph paper, grids, glowing spreadsheets with X and Y grids, or, numbers and letters like A1 and B1 in whatever spreadsheet program you use. Moving into the third dimension can be confusing, even though that's where we live. This is why I called this section Beyond flatland.
Math operations we take for granted in two dimensions or general math turn out to be just different in three dimensions. For example, if you multiply X and Y, you get the same answer as if you multiplied Y and X. Yet in three dimensions, rotations do not behave that way. To see this in action, try taking both copies of this book. (I bought two copies, didn't you? Mom, aren't you reading it?)
OK, seriously, please pick up any two books, real ...
