Syntax: LTYPE INTEGER
or      LTYPE ERASE

   All lines (except for those making up axes and characters) are
drawn with line type INTEGER, meaning:

        0 = solid
        1 = dot
        2 = short dash
        3 = long dash
        4 = dot - short dash
        5 = dot - long dash
        6 = short dash - long dash
	10  erase lines

   LTYPE ERASE is equivalent to LTYPE 10, and will erase any lines
that are redrawn (e.g. LTYPE 0 BOX LTYPE ERASE BOX will first draw a
box, and then erase it). Not all devices can support erasing
individual lines, if yours doesn't you'll have to ERASE the whole
screen.