AT&T 6300 Programmer's Manual page 324

LINE
Statement
Remarks
7-168
The following example draws a line from the
last point referenced to the point specified
(x2,y2). Since no color is specified, the default
color is the foreground color.
LINE -(x2,y2)
The examples below specify start and end
points in absolute coordinates.
LINE (10,10)-(319,199)
'draws a diagonal line down the screen
LINE (10,100)-(319,100)
'draws a horizontal line across the screen
You can specify the color in which the line is
drawn:
LINE (15,15)-(25,25),3
draws a line in color 3
The "b" parameter is used to draw a rectangle
("box") in the foreground, where the points
(xl,yl) and (x2,y2) represent the opposite
corners. In the following example, no color
number is specified:
LINE (10,10)-(100,100)"B
draws a box in foreground
Color may be included as follows:
LINE (10,10)-(200,200),2,BF
fills box color 2