[golf2much]

Mr. Kelley - I mean Mathew
One thing at a time- call me stupid or maybe I just have a communication problem with engineers or similar type folks. So how does your quote above differ from my explanation of parallel.

Let me guess:
In your example, the wall is vertical and the spine is closest to me- and the book is spread open- so the front cover is say angled 45 degrees toward the sky and the back cover is aimed 45 degrees towards the ground - and both are going through the wall at the same angle but different directions? And that's parallel? Just guide me through this example if I missed it- and be very clear so that I can visualize what your describing.
Thanks,
Mike

Mike; "Lines of Intersection" (with the wall). Of course these will be parallel. Any two lines, starting parallel to one another(the book edges), when extended to infinity, their lines of intersection with a common plane (the wall) will also be parallel.

In your example, you are thinking of the surface plane of the book cover, not the line or edge of the plane When the plane of book cover 1 and the plane of book cover 2 intersect a common plane, like the wall, each transcribes a line. These two intersections will be parallel to one another, even though the direction of the two book covers approaching the plane (wall). Try it for your self. Take a hard v=cover book and hold it against a solid surface that you can write on. Hold the book open to the amount of your choice and while hilding it in that position, trace the edge of the book cover where it touches the hard surface. Try it several times, at different amounts of open or closed. The tracings will always be parallel.

G2M