Originally Posted by hhEb09'1

Not only is it not safe, I'd say that that is the third out

If you define an edge, and it's relationship to other edges, it is easy to use trig to determine the value of that relationship. The desription you gave earlier was in three dimensions, and that is what we based the calculations on. However, in four, the fourth dimension is reasonably orthogonal to the other dimensions, so is at right angles to all the others, just as they are to each other. If that makes sense.