Free Born on a Blue Day: Inside the Extraordinary Mind of an Autistic Savant by Daniel Tammet

been very much hoping for girls to help even out the gender ratio. When my mother came back from the hospital she called me downstairs from my room to see my new baby sisters. It was July – the height of summer – and I could tell she was hot because some of the hairs at the front of her brow were stuck to her forehead. My father told me to sit down on the settee in the living room and to keep my back straight. Then, slowly, he collected the babies in his arms and brought them over to me and placed them carefully so that I held one in each arm. I looked down at them; they had fat cheeks and tiny fingers and were dressed in matching pink tops with little plastic buttons. One of the buttons was undone, so I did it up.
    The size of our family brought its own set of challenges. Bathtime was always a rushed and crowded affair. Every Sunday evening at six o’clock my father would roll up his sleeves and call the boys (myself and my brothers Lee, Steven and Paul) to the bathroom for our weekly ablutions. I hated bathtime: having to share the bath with my brothers, having hot soapy water poured from a jug over my hair and face, my brothers splashing each other, the heat of the steam that filled the room. I often cried but my parents insisted that I bathe with the others. With so many people in one house, hot water was at a premium.
    So, too, was money. With five children under the age of four, my parents both stayed at home to help raise the family. The absence of a wage-earner put a lot of pressure on my mother and my father; arguments over what and where and when to spend became more and more common. Even so, my parents did everything they could to ensure we children were never without such things as food, clothes, books or toys. My mother made bargain hunting in the local charity and secondhand shops and markets into an art, while my father proved himself very handy around the house. Together they made a formidable team.
    I stayed away as much as I could manage from the daily hubbub; the bedroom I shared with my brother Lee was where my family knew to find me, no matter what the time of day. Even in summer, when my brothers and sisters were running around together in the sunshine outside, I remained seated on the floor in my room with my legs crossed and my hands in my lap. The carpet was thick and lumpy and clay-red; I often rubbed the back of my hands against its surface because I liked the feel of its texture on my skin. During warm weather the sunlight poured into my room, brightly tingeing the many specks of dust swimming in the air around me as they merged into a single pattern of freckled light. As I sat still and silent for hour after hour, I diligently watched the wash of different hues and colours ebb and flow across the walls and furniture of my room with the day’s passage; the flow of time made visual.
    Knowing my obsession with numbers, my mother gave me a book of mathematical puzzles for children that she had spotted in a second-hand shop. I remember this was around the time I started primary school, because Mr Thraves – my teacher – told me off if I brought the book into class with me. He thought I spent too much time thinking about numbers and not enough time participating with the rest of the class, and of course he was right.
    One of the exercises in the book read like this: There are twenty-seven people in a room and each shakes hands with everyone else. How many handshakes are there altogether?
    When I read the exercise I closed my eyes and imagined two men inside a large bubble, then I imagined a half-bubble stuck to the side of the larger bubble with a third person inside it. The pair in the large bubble shook hands with each other, then each with the third man in the half-bubble. That meant three handshakes for three people. Then I imagined a second half-bubble stuck to the other side of the larger bubble with a fourth person in it. Then the pair in the large bubble needed to each shake hands with