IIRC, in Dirk Gently's, the couch wasn't jammed, it was simply that there was no way in which it could be rotated that would allow it to progress either further

IIRC, in Dirk Gently's, the couch wasn't jammed, it was simply that there was no way in which it could be rotated that would allow it to progress either further up the stairs or back down the stairs.