About 30 years ago I read a short story about an inventor who builds a time machine out of (I think) a Volkswagen Beetle which could only go forwards.
He travels to the year 2100 only to find that time appears to be running backwards; everyone says it's 1900 and as the date passes the original date when a piece of technology was invented (when time ran forwards), it's dismantled and purposely forgotten about.
The inventor is arrested as a "B.A." (Blatant Anachronism) and discovers that 2016 (forward count) was renumbered 1984 B.C. (Backward Count), and from then on the calendar went backwards.
He escapes in his machine to land in 4000 (by the old forward count), only to find it's the year 1, now going forwards again. He's arrested by a Roman soldier who asks him if he's a Christian; all Christians must be put to death as B.A.s.
