Help System (web edition)

FILL=<density value>,<initial value>,<final value> 
(in PLOT operation for curves) draws line segments parallel to Y axis
from the points on the curve to X axis in the interval defined by the
optional parameters <initial value>,<final value>. Default is the whole
plotting range.
<density value> (an integer 1,2,3...) gives the gap between the
consecutive fill lines as a multiple of the plotting step.
YFILL=<density value>,<initial value>,<final value> 
works as FILL but draws horizontal fill lines.
OFILL=<density value>,<initial value>,<final value> 
draws fill lines from the points on the curve to origin (0,0).
IFILL=<density value>,<initial value>,<final value> 
draws fill lines from the points on the curve to the initial point
of the current curve.
  C = More information on curve plotting