I pushed myself off the sofa, went to the desk and pulled a slip of paper (available at all good stationary shops in the year 2002!) from the drawer. I picked a blue ballpoint pen from our Pen Cup, and quickly drew a very rough diagram to show to Zoe.

What I said thus is essentially the proper description of said diagram:

“Imagine that this line is Time—”

“Oh, god. He’s going all Doc Brown on me, now,” Zoe muttered loudly.

“Look, do you want to understand this bullshit, or not?”

“Yes, but—”

“Then sit quietly, stop fidgeting and take notes.”

I imagine that in her head she screamed at me something fierce.

“This line across here is Time. The points at either end – and in the middle – are the Past, Present, and Future. Now, “gliding” back or forwards is simple, I suppose. But the “In-Between” is exactly that: in between these points. Imagine it as potholes in a road, and Time papering over those holes. If you’re not careful, you may slip into one of these holes, and enter this other universe."