To make use of the symbol and wingding fonts, if they are not already
available on your system, first make an extrema/ subdirectory of
/usr/share/fonts and copy the symbol and wingding files to that location.
For example:

$sudo mkdir /usr/share/fonts/extrema
$sudo cp extrema-x.x.x/fonts/symbol.ttf extrema-x.x.x/fonts/wingding.ttf
 /usr/share/fonts/extrema/

