ref: 828c577e03e15f59a69bff965893e3a670a8f10f
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