Syntax: XLABEL str

   Write the label "str" centered under the x axis made by BOX.
If you think that the label is badly positioned you can say things like
        XLABEL \raise-500My X-axis Label
(providing that you use TeX-style fonts, of course)

If the label is too tall it may overlap with the numerical tickmark
labels. If VERBOSE is one or more, you'll be warned about this, and
a suggested change to the plot LOCATION will be suggested. This moves
the entire plot; it is your responsibility to reset it later if appropriate.

   If EXPAND is exactly 1, and ANGLE is exactly 0, SM will attempt to
use a hardware character set. To avoid this use EXPAND 1.0001, or
preface the string with an explicit \r.