This honestly isn't meant to be mean, but I've just read something on another thread which has really tickled me. Someone has described her ex and his new partner as just having had "two baby twins together".
Well obviously there are two of them if they're twins, obviously they are babies if they've just been born, and obviously (by the way it's described) the babies belong to both members of the couple. So of the four words, three are unnecessary.
Just thought that was a rather glorious example of textbook tautology which fellow pedants would appreciate.