Why is everything considered a curve?

Don asked - I'm sure this has something to do with Nurbs, but can someone explain why
everything is considered a curve? (Or is at least everything 2D seems to
fall under the curve heading)

Safak answered- It doesn't necessarily have anything to do with NURBS. "Curve" is a more
general term than a line or a circle. Curve can be any inherently 1D (not
2D) object and can "accidentally" take the form of a line, an ellipse, a
rectangle, a trefoil knot,... etc. These other terms are not exceptions but
special cases.

In terms of dimensionality:
Point: 0D
Curve: 1D
Surface: 2D
Volume: 3D
...etc

You can draw a curve inside/over 1D, 2D, 3D, 4D... etc spaces/objects. You
can draw a surface inside/over 2D, 3D, 4D...etc spaces/objects. You get the
picture. Another way to think about is that a curve is a sweep of a point, a surface
is a sweep of a curve... etc. Safak Rhino Newsgroup
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