This often comes up in class when we’re talking about volume and area and Dr Who fans are always especially keen to know. My effort to explain the dimensions is to try to link it to English as follows:
One dimensional characters are just a line, a name or a signature. You don’t get much sense of the person.
Two dimensional characters are much better. You can get a 2D photo of these and imagine what they’re like. You can see expressions on their faces and decide whether they look mean, happy, funny or kind.
Three dimensional characters are better still. You can pinch them, punch them, first-of-the-month them and see how big their noses are if you walk around them.
All of these characters are still, though, Like Madame Tussaud’s figures, they don’t move. So better than all of these are four-dimensional characters. You can spend time with these characters, have midnight feasts with the,, go on holiday with them and when you throw a stinkbomb at them they will chase after you.