He smiled and I wondered whether I’d said something stupid.

“Sort of. But what your Alexandre Dumas liked best was stuffing his face and running after women!”

I didn’t dare to contradict him, because I didn’t have the facts, but I promised myself I’d check up on it anyway.

“And writing too, though,” I said, in his defence.

“Yes, of course, writing too. But not as much.”

“Well, you have to admit it’s a lot less fun!”

We were lined up along the wall outside the maths classroom, waiting for people to come out from the last lesson. I looked around for Marie but all I could see was her mop of curly hair going past, and I noticed that she was quite a lot taller than me. She was very well turned-out, with neat clear lines and nothing slipping over into the margins. I thought about what Dad often said to encourage me to take pride in my appearance: it’s the feet that reveal proper care and true refinement. I looked down and saw that Marie’s socks were indeed impeccable: ultra white and without a wrinkle, all the way up to her knees.

I felt all blurry in comparison, as though I was about to dissolve.

In class, the teacher handed us a paper with some geometric shapes and questions on it and I realized straight away that it was difficult. I’d spent the previous evening poring over the Krebs manual and various journals to get to the bottom of Dad’s question about innovations in the 1901 Paris–Berlin motor race. But I’d fallen asleep without finding the answer, and to cap it all I’d forgotten to do my homework. So I began by sharpening my pencil to get me in the right frame of mind and then I read the first question:

Construct an isosceles triangle ABC with base BC. If E is the reflection of A in the line BC and if T is the translation that maps B to A, prove that the image of E after translation is C.

Checkmate, no doubt about it. I thought about the chess player Reshevsky, who my respectable Egyptian had been talking about. It would have been good to be an Escape Artist like him, with an instinct for survival that would have enabled me to triumph over triangles of any sort; but sadly that wasn’t the case. To kill time I dropped my metal ruler, which irritated more or less everyone, including our disabled teacher.

“Victor! I’m going to move you… Take your things and go and sit … over there, next to Marie. At least there I can be sure you won’t get distracted.”