Autoshape

The Autoshape tool allows you to quickly create standard shapes just by sketching. The sketched shape will automatically recompose into a standard object depending on the shape of the sketch.
The objects include:
Lines, Polylines, Rectangles, Polygons, Triangles
Arcs, Circles, Ellipses, 
Ellipse / Circles
If the sketch closely approximates a elliptical path an ellipse will be generated.

If the radii of the computed ellipse are almost equal, then a circle is drawn.

If the sketch closely approximates a circular path but is open an arc will be generated.

 
Line
A single quick dash will result in a line.

Polyline
If the end points are closely located the resulting polyline will be closed.
If the angle between the nearest computed line segments is close to to 90 degrees, right angle is created.

A closed polyline with 3 points becomes a triangular Polygon.

A closed polyline with 4 points becomes a rectangular Polygon.
Bezier Curve
If the sketch does not approximate a regular shape a Bezier curve will be created. The curve can be closed or open.