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).
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