ref: 358551de19c9ff5bab9cd9c98769224f63fb7e94 dir: /sys/lib/troff/font/devutf/charlib/bx/
/build_bx { pop size 2 div /side exch def currentpoint newpath moveto 0 side rlineto side 0 rlineto 0 side neg rlineto closepath fill } def