4.4BSD/usr/src/contrib/groff-1.08/tmac/tmac.pic

.de PS
.br
.sp .3v
.ne 0\\$1+1v+\n(.Vu 
.in \\n(.lu-\\n(.iu-0\\$2/2u>?0
..
.de PE
.in
.sp .3v+.5m
..