All commands must begin in column 1. Each may be abbreviated to its first 4 letters although the full word is given in the catalog. The command line may be up to 120 characters in length. When a number or numbers follow a command there must be at least one space after the command word. Numbers may be separated by a comma or spaces.
Any line beginning with a blank is treated as comment.
The default value is one half of the larger of the two base dimensions. When this command is furnished numerals and tick marks are given to the x and y axes and these are plotted as if they were fixed in a horizontal plane corresponding to the smallest function value. The annotation for the x axis labels it as if it extended between x1 and x2, irrespective of the array dimensions or its actual length in inches. If you set x1 equal to x2 the x axis is not annotated. Similarly for y1 and y2.