Curve Lines can be drawn that have multiple smooth inflections between Start and End Points (sinusoid shapes).
Figure 10.17 Curve Line
Curve Lines are controlled by pairs of Control Points and a single pair of Start and End Points. Control Points and End Points can be stretched to reshape the Curve Line later.
Each Segment of the Curve Line will become a separate object.
Use Polyline if you want to draw a single object with multiple curved segments.
Curve and Straight lines can not be mixed in the same Polyline.
Figure 10.18 Curve Line with Control Points and Start/End Points