Hello John,
>
> I think, in the end, absolutely anything (or things) that cast a shadow(s)
> on any surface (plane or not) can be used to describe a sundial!!
However,
> the markings get very complex.
Agreed, (not to mention the maths)!!
> Thus, to answer your question, the two threads or edges don't have to be
> parallel to the dial plane to produce a dial. What most people understand
> by a "classic" bifilar dial does have this feature though. It leads to
dial
> markings which can be sensibly described mathematically, and are logical
to
> look at. My personal view, for what it's worth is that we should reserve
> the name for these cases, and describe the more exotic variants in
specific
> detail.
>
> Best regards,
>
> John
I would concur with earlier postings then, suggesting that perhaps some
further terminology might be useful.
thanks for the clarification
Sarah
