ref: acfc389bb90944f3ac1200eec4a80b49adaf4e6a
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