On Mon, Mar 23, 2009 at 7:25 PM, Christopher Hickman
<tophu@xxxxxxx> wrote:
On Mar 23, 2009, at 3:34 PM, David L. Willson wrote:
Every ray must be perpendicular to every other ray.
Clarifiers, if needed:
- "A ray is not considered perpendicular to itself, so a koan with only one pyramid cannot have the BN."
- "Rays pointing in opposite directions are parallel, not perpendicular, no matter whether the rays touch the opposing pyramid or not."
I don't understand what this means, even with the "clarifiers."
Parallel is like the rails of a straight section of railroad track.
Perpendicular is like an upright flagpole next to the railroad track.
A square's opposite sides are parallel to each other. Its adjacent sides are perpendicular to each other.
This bit of geometric definition is so elementary that I strongly suspect I don't understand what it is that you don't understand.