Line and Point Styles

The following appear in the plot command after with lines or with points, and determine the appearance and/or size of the lines and symbols drawn.
lt <option>
Define the "line type" -- its color, for our purposes. Option 1 is red, 2 is green, 3 is blue, 4 is purple, 5 is... (experiment for yourself).

lw <option>
Define the line width -- 1 is normal, increasing numbers give thicker lines.

ps <option>
Define the point size -- a multiplying factor over the standard size.

pt <option>
Define the point type -- specifies the number of sides or spokes in a not particularly obvious way (can be redefined).