A drawing I started two weeks ago, and every day since I've worked on it, crept up on it to take it unawares, corrected it, erased it - it's a large charcoal drawing on thick paper - hidden it away, displayed it, reworked it, looked at it in a mirror, redrawn it, and today I think it's over.
It's a drawing of Maria Muñoz, the Spanish dancer. In 1989, with Pep Ramis, the father of their three children, Maria founded a dance company called Mal Pelo. They work in Girona in Catalonia and perform in many European cities. Five years ago they invited me to collaborate with them.
Collaborate how? I'd watch them for hours improvising and rehearsing, singly, together, in couples. And sometimes I'd suggest a twist in the story-line or a word or two or an image that they might project. I suppose they used me as a kind of narrative clock.
I watched them preparing meals, talking round a table, comforting children, mending a chair, changing clothes, exercising and dancing. Maria was, by far, the most experienced dancer but she didn't direct, rather she set an example, often by showing how to take risks.
The bodies of dancers with their kind of devotion are dual. And this is visible whatever they are doing. There's a kind of Uncertainty Principle which determines them; instead of being alternately particle and wave, their bodies are alternately giver and gift.
They know their own bodies in such a penetrating way that they can be within them or before them or beyond them. And this alternates, sometimes changing every few seconds, sometimes every few minutes.
And it's this duality of each body which allows them, when they perform, to merge into a single entity. They lean against each other, they lift, carry, roll over, separate from, co-join, buttress each other so that they are two, three, four bodies become a single dwelling, like a living cell is a dwelling for its molecules and its messengers, or like a forest is for its animals.
And it's the same duality which explains why they are as much intrigued by falling as by leaping, and why the ground challenges them as much as the air.
And I say all this this about the company, Mal Pelo, performing, because it's also a way of describing Maria's body.
One day watching her, I started to think about the late Degas bronzes and drawings of nude dancers. I asked Maria if she would pose for me. She agreed. She posed for several hours in a Paris dance studio. Also in the studio were the film crew of Artangel's TV series "Life Class".
Let me show you something, she suggested, it's a preparatory position we take on the floor like this and we call it the Bridge, because our weight is suspended between our left hand palm down on the floor and our right foot also flat on the floor. Between those two fixed points the whole body is expectant, waiting, suspended.
We forgot about the film crew who were very discreet. More than that, their presence allowed us to forget ourselves. We thought only about the pose.
Drawing Maria in the Bridge position was like drawing a coal miner working in a very narrow seam. Maria's body was highly feminine, but what was comparable was its visible experience of exertion and endurance.
Its duality was evident in its calm - her relaxed left foot lay on the floor like an animal asleep - and in the grid of forces in her hips and back was ready to challenge, at any moment, any dead weight.
Finally we stopped. She came to look at the drawing. We laughed together.
Then the days of working at home on it. The image in my head was often clearer than the one on the paper. I redrew and redrew and redrew and the paper became grey with alterations and cancellations. And the drawing didn't get better, but gradually she, just about to stand up, was more insistently there.
And then today, like I said, something happened. The effort of my corrections and the endurance of the paper have begun to resemble the resilience of Maria's own body. The very surface of the drawing, its skin, not its image, makes me think of how there are moments when watching a dancer, moments that can make your hairs stand on end.
We who draw do so, not only to make something observed visible to others, but also to accompany something invisible to its incalculable destination.