Professor: That’s a nice idea. I see you’ve called your [1] ‘the Rockpool’; why is that?
John: Basically because it looks like the rock pools you find on a beach. The top is made of [2] so that you can look down into it.
Professor: And there’s a stone at the [3]. Is that just for [4]?
John: Actually it does have a [5]. Instead of pushing a button, you turn the stone.