‘So, Saara,’ the hairy doctor says, taking hold of my arm. ‘Now, I’ve got an important question. Tell me your favourite thought.’

Every now and then, you meet grown-ups who take children seriously. They ask interesting questions and listen to your answers. You can be straight with grown-ups like that. You can ask them things and they give proper answers, and they also tell you if they don’t know. I decide to test this doctor.

‘I like to think about time,’ I answer.

Just then, the doctor yanks my arm with terrible force. My shoulder lets out a cracking sound and my mouth lets out a cry. The doctor looks on with his calm eyes.

‘Time? That’s a splendid answer. Try and twist your hand now.’

‘Saara? Saara?’ Dad’s shouting behind the door, rattling the door handle.

‘It’s OK, it’s OK,’ I tell him.

The rattling stops.

My shoulder moves normally in its socket. The pain has gone, too. I wonder for a moment if I should be angry, or thump the doctor on the nose, but this time thing interests me enough for me to decide to let it go.

‘What is it about time that you find particularly interesting?’ the doctor asks.

I wait for a moment, to see if he’s planning to grab anything again, but as he’s not touching me, I decide it’s a genuine question.

‘That time moves backwards, like this.’ I show him with my arm, which is now back in its place. ‘Here is now, and here are the things that happened a long time ago. And it moves like this.’

The doctor nods his curly head.

‘But sometimes, pieces come loose and they don’t move with time but instead stay here, always,’ I go on. ‘Everything else moves backwards, but those pieces stay here. You can forget them, but when you remember them again, they’re just as close as they were at the beginning.’

‘Right,’ the doctor says.

‘Have you got pieces like that?’ I ask.

‘Of course,’ the doctor replies.

I wait, and he goes: ‘One could be when I first held my daughter.’

‘Any others?’

‘Another one could be when my son started cycling without stabilizers, and I let go.’

I try to imagine the hairy doctor letting go of the bike and watching the boy cycling off. Then I say, ‘I’ve got pieces of my mum. They’re clear but they’re loose.’

‘I don’t think it matters,’ the doctor says.

‘Really?’

‘I think you can let the pieces be as they are.’

‘OK,’ I answer. ‘I’ve also got a medical question. It’s about blood.’

‘Let’s hear it,’ the hairy doctor says.

‘Why does blood look blue through the skin but red when it comes out?’