[O.B.Left]

Nice one Bucket. The word "Perpendicular" works nicely too.

I agree Jerry , pictures are best when it comes to describing geometry. Words often make matters seem more obtuse. Imagine studying high school geometry but in words only, no diagrams. If I could ask Yoda for one thing this christmas it would be for more diagrams.

Take for instance 1-L-21:

The relations of all Machine positions and motions can be described by a geometric figure.

That would be a nice wiki post for guys to add geometric figures to. Even if its pencil sketches.

Homer gave us a few diagrams, but I do wish he'd given us more. Even the geometry of the circle was not illustrated in the book. By the way, there's one right there....... the geometry of the circle , in 2D can lay flat against the Inclined Plane. Somebody could draw that easily. How 'bout the law of the triangle? Or how the bending right elbow cocks the left wrist or Single Horizontal as a non planar, cone shaped motion or or ....

Perhaps Homer thought it was all obvious?