The lines style connects adjacent points with straight line segments.
It may be used in either 2D or 3D plots. The basic form requires 1, 2, or 3
columns of input data.
Additional input columns may be used to provide information such as
variable line color (see rgbcolor variable (p. )).
2D form (no "using" spec)
1 column: y # implicit x from row number
2 columns: x y
3D form (no "using" spec)
1 column: z # implicit x from row, y from index
3 columns: x y z
See also linetype (p. ), linewidth (p. ), and linestyle (p. ).