15.4.2 Line Styles
Line styles are specified by the following properties:
     
- linestyle
- May be one of
          
- "-"
- Solid line.  [default]
          
 
- "--"
- Dashed line.
          
 
- ":"
- Dotted line.
          
 
- "-."
- A dash-dot line.
          
 
- "none"
- No line.  Points will still be marked using the current Marker Style. 
 
 
- linewidth
- A number specifying the width of the line.  The default is 1.  A value
of 2 is twice as wide as the default, etc.