ref: 1d0b9d7088f61fd3e28dada8e8e97abf3eac69f9
dir: /sys/lib/troff/font/devutf/charlib/sq/
/build_sq {
pop
size 2 div /side exch def
currentpoint
newpath
moveto
0 side rlineto
side 0 rlineto
0 side neg rlineto
closepath
font B eq {fill} {stroke} ifelse
} def