They were identical then in a way they are not now — at eight there are eleven differences and at five there were two, and the two were a scar on Nora’s left eyebrow from a coffee table in Charlotte and the fact that Maya’s ears are very slightly asymmetrical.

I used the scar.

Constantly, and with a kind of low-grade panic, in every room, for months, checking an eyebrow before I said a name.

Evelyn knew within about a week.

She did not say anything for six weeks and then she said something in a kitchen, at a moment when nobody was upset, which is how she does everything.

She said: “You’re checking the eyebrow.”