Marie and I reached the playground and I left her there, just like a towplane releasing a glider. I watched her walk steadily off. Her lips were moving very slightly and I realized she was counting her steps. She must have done the same thing when she gave her note to the teacher and got back to her own desk. The very thought of it nearly made me keel over in admiration, with tears in my eyes. Well, I’m exaggerating a bit, but you can’t blame me.

After school, on the way home, she confirmed it: she’d been calculating distances for weeks, and now they were all recorded in her brain. She’d turned the school into an immense geometrical plane, divided up into carefully measured squares.

“For instance, you see, it’s twelve steps from your Egyptian friend’s lodge to the lockers. From the school gates to Lucky Luke’s office it’s twenty-eight steps if you go on the right-hand side, thirty-seven if you go on the left. From the toilets to the canteen it’s seventy-eight steps, unless they’ve put up display panels for an exhibition, in which case you have to go round them, making a hundred and seventeen steps.”

We walked on towards the village. I was amazed because Marie seemed to know where she was going. I even wondered for a moment if she was having me on about going blind, but then I felt really guilty. And in any case, just when I was looking the other way and didn’t have time to react, I heard a noise like someone banging a gong: I turned to see her on the ground beside the postbox she’d crashed into. She was rubbing her forehead, where a big red lump was forming, with a bleak look on her face. I could see how despondent she was. She seemed so strong and proud, even more so since she’d been hiding her disability, but all this was a huge deal in terms of her dignity. In actual fact she was like everyone else: lost and all alone in her misfortune. She was trying not to cry. It was odd to see translucent tears forming in those eyes that could no longer see.