Many commands require numerical values to be passed to them. This is done
by entering the values, separated by commas, before entering the command
itself. For instance, the command  A  with argument 8 is simply entered as
8 A.

The convention for naming numerical values passed to commands is:
  No values:      NONE
  One value:      ARGUMENT
  Two values:     RANGE
  Three values:   LIST

Many commands also leave numerical values to be processed by the next
command in a command sequences. For instance, the command  A  leaves an
argument indicating an ASCII-value. The following command might use this.
It is also possible that a command leaves values which would confuse the
next command. In that case, use of an ESC will cancel any argument.