Later, we wandered to the park. I felt the air on my scalp as she must have done on hers. We made a tour of the Ilm then headed back on ourselves. By the cafe there were mothers and children eating sandwiches as pigeons waited for scraps. The breeze moved the toy sailboats on the pond. We watched the kids play then headed to the bridge. ‘Are you warm enough?’ I asked.

She poked her bald head out from an orange scarf. ‘Just about. I hadn’t banked on all that hair keeping me warm.’

‘You look like a monk.’

‘So do you.’

We lay down by the river and watched the clouds pass. I wondered what everyone else was doing. I guessed Jenö would be shaving Walter’s head just as Charlotte had done mine. She hadn’t mentioned Kaspar and Irmi – maybe they had both exempted themselves. I wouldn’t have put it past either of them to be more sensible than us.

‘Let’s play the hiding game,’ she said. ‘You’re the sleeper.’

This was a ritual we kept. One person closed their eyes and counted to twenty. The other found an object and held it in their palm, describing to the ‘sleeper’ what they held in three words. I opened my eyes. Her hand was a fist.

‘Refractive. Colourless. Very wet,’ she said.

‘That’s four words, so you’re cheating.’

‘Wet,’ she said, ‘if I can’t have “very wet”.’

‘It wouldn’t be water?’

She opened her palm, some drops fell. ‘How did you guess?’

‘All right, you be the sleeper.’

She counted with her eyes closed.

I held out my hand to her. ‘Encased. Minced. Piggy.’

‘Sausages?’ she said, her head cocked, confused.

‘Wrong.’ I opened my fist. ‘Imaginary sausages.’

‘Doesn’t count. It has to be here. Materially here.’

‘How do you know it isn’t? The whole river might be atremble with sausages if only you could see its singularity.’

‘Even Master Itten would suggest the river is only water.’

‘Master Itten can’t always see what’s in front of him. Just look at his attitude to my painting.’

I regretted this as soon as I said it. I didn’t want us to argue about Mr Steiner’s studio, not when we had been given a day as divine as this one. And, like a gesture from the gods, without warning the clouds split and the sun poured jewels so that the river heaved and brimmed.

‘Charlotte! Look!’

The trees were struck yellow in the hectic blaze, and the grass beyond was as vivid as a painted field, and the Ilm was so bright that I wondered if Jerusalem hadn’t indeed discovered itself.

Charlotte herself was spectral; transparent. She beamed!