ref: e74a87d537dfd2ed817ba94314df7c517b51d65a
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