BBC Middle East Editor Jeremy Bowen's diary of the conflict between Hamas and Israel.
Ahmed will be scarred for life by the experience he has had, psychologists say
Ahmed, a 16-year-old boy, only became animated when he talked about his dead pets. Even then the mask that his face has become shifted only slightly.
He pointed towards a pile of rubble: "That was my house. We were living there and we were very happy. The Israelis destroyed my house and the other houses before they pulled out."
'I had two goats and a donkey and they killed them. And they killed 10 pigeons, and our chickens and a cockerel and two ducks. The pigeons and the goats were mine. The rest belonged to the family.
"I loved seeing my pets grow. I wanted to see their babies. It makes me very sad that they killed the animals, the donkey, the goats, the pigeons and the ducks.
"Why? I don't know why they kill animals. I don't believe birds can harm them. My white pigeons were shot. I know that because I found their bodies."
Ahmed talks with some expression about the death of his pets because he is trying to clear his mind of everything else he witnessed in Gaza City.
Three of my brothers died next to me. I had been lying next to my brother Ismail
Ahmed says that after the Israeli soldiers came to his street he was confined with 90 members of his extended family in a house just opposite his own. Other witnesses confirm his story.
After more than 24 hours, the house was hit by some sort of projectile and there was a big explosion. Local people say that 29 people were killed.
When representatives of the International Committee of the Red Cross (ICRC) reached the site more than 48 hours later they found part of what they say looked like a high-tech rocket in the building.
They also found children who had been stranded there with the bodies. One of them was Ahmed.
When he talks about it his face is a mask again. When the explosion happened he thought at first that he was dead.
"But I opened my eyes and moved my arms and legs and I realised I was alive. But I couldn't speak or get up," Ahmed says.
I asked him what happened to his family.
"Three of my brothers died next to me. I had been lying next to my brother Ismail. My head was a half-a-metre from his. My brother Yacoub was hurt. There was a hole in his stomach that you could have put a coffee cup into."
And his mother was killed. Ahmed says he thinks of her every day.
The survivors were allowed to leave by the soldiers who had told them to stay in the house. Ahmed could not walk, so the others promised to go for help.
He says the time they were there in the house was terrifying. They found a small amount of water. He would drag himself to the door to watch the Israelis. He saw them bulldozing the mosque flat.
The ICRC says Israel refused to let them get to the wounded for more than two days.
That is why they broke their usual silence to issue an angry statement saying it looked as though the Israeli army had not fulfilled its obligations under the laws of war to treat the wounded or arrange for their evacuation.
The house the soldiers commandeered is 10 paces away from the place where Ahmed and the others waited for help for more than two days with the bodies.
His father survived, as did four younger brothers and two older sisters. He has not gone back to school yet, because he says his clothes and his books were destroyed when his house was bulldozed. So was the bicycle he used to get to school. Maths was his favourite subject.
Ahmed has had some sessions with experts in the trauma that children suffer when they experience violence.
In Gaza, they have developed considerable expertise. They say he needs a lot of time and treatment, and even then the experience he has had will scar him for life.
The doctors were encouraged that, when he spoke about his mother, his expressionless mask slipped slightly, and he looked as if he was struggling not to cry.
The psychologist and psychiatrist who were with him said that he was going to have to go through a great deal of emotional pain, the pain that he was trying with all his might to suppress, if he was to have any hope of getting better.
No wonder Ahmed finds it easier to talk about his dead pets.
Other previous diary entries by Jeremy Bowen: