ref: 3dd92d8f0badea8dc2cf20cc2a8c3aee390daee6
dir: /sys/lib/troff/font/devutf/charlib/rc/
/build_RC {
pop
size 4 div /side exch def
currentpoint
newpath
moveto
0 side 1.5 mul rmoveto
0 side rlineto
side 2.5 mul 0 rlineto
0 side neg rlineto
closepath
fill
} def