The Figure shows three sets of contours and winding numbers for points inside those contours. In the left set, all three contours are counterclockwise, so each nested interior region adds one to the winding number. For the middle set, the two interior contours are drawn clockwise, so the winding number decreases and actually becomes negative.
The winding rule classifies a region as inside if its winding number belongs to
the chosen category (odd, nonzero, positive, negative, or "absolute value of
greater than or equal to two").