The theme of photography assignment is the concept of creative window and mirror door. Pictures don't need to contain these things, but they need to imply one of them, such as

Your question is more like a literary problem, or a creative problem of the director and screenwriter department. Consider thinking space, imagination and the ability to describe abstract things. If I understand correctly, I actually mean what the words door and window can describe. And record your thoughts on this matter by photography.

If you shoot the starry sky, it can be described as a stargate, an alarm clock and the like can be called a dimensional gate, a beam of light can be a door of hope, a book can be a door of knowledge, and so on. In short, this proposition can be completed as long as the themes of time and space are intertwined.