We are often told time is like a river. Are there other useful analogies for time? For example: Time is like a bowl of jello with fruit: time is the jello and events are the fruit stuck in it. I guess what I'm really asking is does time have to flow? Is there another way of thinking about time?

Thinking of time as flowing obscures far more than it clarifies, on my view, and I think that the river analogy is dangerous. Anything that flows flows at some rate. How fast does time flow? Sixty minutes per hour? The image raises the prospect of a supertime against which the flow of time occurs, and that raises a nasty regress. Better to think of time as a dimension of the universe, but one that is anisotropic,t hat is, one in which going in one direction is different from going in another, unlike, say, East-West travel.