How many intersection points can a straight line and a polyline of three links have?

A straight line and an open polyline, consisting of three connected segments, can have:

0 points of intersection, in the case when none of the links of the broken line have points of intersection with a straight line;

1 point of intersection, in the case when only one link of a broken line has a point of intersection with a straight line;

2 points of intersection, when, respectively, 2 links of a broken line intersect with a straight line;

3 points when each link of the polyline intersects with a straight line.

If the polygonal line is closed, then there can be only 2 intersection points.