I wonder what does this mean: Point travels around curve. I try to figure out some math explanation in the book and I can't move forward because I can't understand these words.
I can understand when point intersect curve (i.e. lie on it). I can understand when curve envelopes around point(e.g. the center of circle, ellipse). But what doses that mean when Point travels around curve ? Could you please describe this process in more details?
P.S. If that help this is slice from the book:
A third rule is the nonzero winding rule. The winding number of a point P with respect to a curve C that does not contain the point is defined as follows. Consider a point Q that travels once around C. The endpoint of a vector from P to Q, after normalization, travels along the unit circle centered at P. If we imagine the track of this endpoint as a rubber band, and let the band contract, it will end up wrapped about the circle some number of times. The winding number is the number of wraps (for clockwise wraps, the winding number is negative).