2D form (no "using" spec)
1 column: y # implicit x from row number 2 columns: x y3D form (no "using" spec)
1 column: z # implicit x from row, y from index 3 columns: x y z
See also linetype, linewidth, and linestyle.
Copyright 1986 - 1993, 1998, 2004 Thomas Williams, Colin Kelley
Distributed under the gnuplot license (rights to distribute modified versions are withheld).