After Otti and Anni’s dire warnings that morning, I taught in the afternoon. I had three objects assembled before me: a lamp, a chair and a tea glass. I wanted to show the students the will to form; that good design might be made from a few simple shapes, or maybe even just one. I went off for a while on my theme – the criminality of ornament – then I remembered what we had come to do. I tried to temper my excitement because I thought maybe it was obvious that I wasn’t all there. ‘Each design,’ I said to the babies, ‘should consist of no more than a few simple parts.’

Michiko and Howard exchanged looks, and the rest of the class was silent. Maybe I’d already said all of this.

‘The gramophone needles,’ said one, a woman whose name I frequently forgot, and who knew I frequently forgot her name. ‘You said we were going to present our findings today. Because we ran out of time last session.’

‘Oh, yes,’ I said, having clean forgotten I’d set them that task. ‘Use them for your Metal Ball costumes,’ I said, bungling it. ‘I’ve no idea what I intended us to do with them.’

I could tell she was unhappy with my sloppiness, but I ignored her. I felt adrenal. I was a powerful teacher, and I had more important things to communicate. ‘Look at this lamp,’ I said, quite loudly, and pointing to the Wagenfeld and Jucker lamp. ‘Spherical shade, cylindrical shaft, and a circular base to mirror its top. It’s perfect. Three variations of the circle. And yet all its parts are visible; even the cord and switch. It shows its functions. It hides nothing.’

Here, as Marianne had said, was the ontology of the lamp.

I moved on to Josef’s tea glass. It was a triumph of design, though it had not sold well: the story, really, of the Bauhaus. ‘Heat-resistant glass, brushed chrome, but what about this cup makes it special?’

Michiko raised her hand. ‘The handles.’

‘Exactly. One handle for the server to give: horizontal. But it’s much easier for a human hand to receive on the vertical. Two handles, two directions, one tea glass. It’s a wonder no one’s ever thought of this before. This happens when you will simplicity.’

I passed the tea glass to Michiko using the vertical disc, and she took it with the horizontal, and smiled. My teaching leapt with brilliance. ‘It’s wonderful, isn’t it?’

Nods all round.

‘You said it was the other way around,’ the nameless woman said.

‘What? Did I?’

‘You said horizontal for the server, vertical for the receiver. Then you did the opposite.’