Then I started on the emails. At work, Greg had written twenty or thirty a day, sometimes more. Based on each one, I wrote “O” for office in the appropriate slot on the card. Some were in clusters. He had a habit of sending a flurry of messages as soon as he arrived at work, another just before one o’clock and another at around five, but others were dotted through the day. It didn’t take me much more than an hour to work my way through the emails, and when I was done, I stood back and surveyed the result. The chart was already satisfyingly shaded in, and there was still so much to do.

The next day I invited Gwen around. I said it was urgent but she was at work and didn’t reach me until almost six. When she arrived I hustled her through to the kitchen, boiled the kettle and made a pot of coffee.

“Would you like a biscuit?” I said. “Or a slice of ginger cake? I made both this afternoon. I’ve been busy.”

Gwen looked amused and a bit alarmed. “Some cake,” she said. “A tiny slice.”

I poured the coffee and gave her the cake on a plate. I wasn’t hungry. I’d felt I needed to cook but not to eat.

“So what’s up?” said Gwen. “Did you summon me here to try the cake? It’s great, by the way.”

“Good, have some more. No, it’s nothing to do with that. Drink your coffee and I’ll take you through.”

“Take me through? What is this, a surprise party?”

“Nothing like that,” I said. “I’ve got something to show you. I think it’ll interest you.”

Gwen took a few quick gulps of her coffee and said she was ready. I steered her along the hall and into the living room.

“There,” I said. “What do you think of that?”

Gwen stared down at the four large pieces of card, now covered with marks and stickers, all different shapes and colors. “It looks lovely,” she said. “What’s it meant to be?”

“That’s Greg’s life in the month before he died,” I said.

“What do you mean?”

I explained to Gwen how the charts represented days and sections of days. I told her about the timed emails and my own memories and how I’d even found receipts from the sandwich bars where Greg had bought his lunch. All the receipts, whether for food or petrol or stationery, gave not just a date but an exact time, to the minute, when the purchase was made. “So all these stickers, the yellow circles and the green squares, they show moments when I know exactly where Greg was. It’s pretty amazing, isn’t it?”

“Yes, but—”