
That day, I prepare students for a workshop in which we will explore movement and gestures, using the sensors of smartphones. For the most part, the students are not scientists. At the end of the course, a design student says to me:
“You should have a look at the work of Fabienne Verdier. Some of her paintings resonate with what you are saying, I think.“
I have never heard of Fabienne Verdier. I then forget that advice. Two days later, I get an email. Subject: “Fabienne Verdier“. In the email, the picture above.
I remain banned. The reproduction on the screen certainly does not do justice to the real painting in large format. But I feel it immediately: this artist will lead me to revisit my representations of movement. In her paintings, the line represents essential, pure, simple elements of movement, close to those I play with in Newtonian physics when I teach these fundamentals.
Fabienne Verdier was an art student for 10 years in China in the 1980s. I am a visiting professor at Tsinghua University, and I love working with Chinese students in workshops. But the few weeks spent in Shenzhen only allow me – at best – to measure the difficulty of grasping the roots of her work in Chinese culture. Yet, when I contemplate her work, it seems to me that she develops, from this story, through her own creativity, a vision of movement that touches on the universal.
I am therefore trying here to understand, as a physics teacher, why I feel in an immediate proximity with her works, when a priori, everything separates us.
The movement explored by the line
The artist’s body draws traces, walking on the large surfaces that serve as supports for her painting. In the beginning, there is therefore the line. Thin or thick. Pure or tormented. In an interview, she underlines:
“I have been working for 30 years on this energy of matter in space which is this unique brushstroke. “
The very large canvases are also there to allow a real immersion of the viewer in the painting.

Today, the physics of movement is still often taught with chalk and a large blackboard. The physicist’s attempt to represent movement with lines is a matter of course. For example, when, at the beginning of the 20th century, Jean Perrin observed the permanent and disordered movement of microparticles in water under the effect of thermal agitation – (Brownian motion) – he represented it by broken lines on paper, knowing that these lines did not represent the trajectory of the microparticle he was observing under the microscope – this is a convention intended to facilitate understanding.

In kinematics, the line is the tool for representing the movement of a point moving in space. The Cartesian coordinates of the moving point are: x(t), y(t) and z(t). Their knowledge at any point of the trajectory and as a function of time is a complete description of the motion, within the framework of Newtonian physics. We can combine infinitely point movements, from left to right, from front to back, from top to bottom and their symmetry. Just as tennis players do with the ball, whether or not they spin on it.

We spin a smartphone held by the hand at the end of the arm. Its trajectory is close to the circle. Above, this is the image without any processing of the data acquired by its micro accelerometer during this movement: ay versus ax. Reproducing by calculation the general shape of this trace is a bachelor exercise, say, of a good level.
Finally, I also teach these elements of movement identified by the artist and on the basis of which she proposes to look at the movement of the world with renewed attention. That’s what interests me.
An abstract language around a movement
“I wanted to create an abstract language around constant movement, around the energy of life. “says Fabienne Verdier.
The fundamentals of the representation of movement, in her paintings, make us experience on a surface the changing world through the displacement of her body. Her work with the musicians of the Julliard School in New York brings her even closer to this primary reality: the representation of movement is much more than a photo of a fixed trajectory. For the scientist, to know movement is to have the position at all times, something like the entire film. And yet it is indeed the production of singular traces of movement on a canvas that she explores to give us, beyond any figuration, this momentum of movement in one motionless line. In this respect, the Roland Garros poster is particularly successful.
The circle
There is the curvature of the lines in the plane. Constant curvature of the above incomplete circles. Variable curvature below.

The straight line

The simple straight line makes it possible to underline – as with incomplete circles – this obvious fact: all movements around us have a beginning and an end.
The periodic movement
To suppress start and stop, start and stop, there are round trips. The periodic motion. The oscillating pendulum. The illusion of permanence.

From small to large. And vice versa?
In the images in the tables above, the line is complex. It goes far beyond an ideal line. The simple vertical straight line is thick. Its beginning is rounded. Its end is spread out. Spots and disordered fine lines revolve around it.
Still in the same interview, Fabienne Verdier expresses her fascination with the fractals introduced and popularized by Benoît Mandelbrot.

It is always surprising, but if a motif repeats itself indefinitely, one can get lost in it and it is indifferent because it is the same at all scales. The question of movement at different scales is fundamental in mathematics, physics, mechanics… It was questioned at length by Jean Perrin at the beginning of the XXᵉ century. Fabienne Verdier finds here the necessity to play by the line with movements that keep their essential characteristics at different scales.
Turning point

She adds the change of direction on the spot by a rotation at one point: in short, she turns around her brush thanks to the handlebars. She moves forward while breaking the trace left behind by this enormous brush on these large formats placed on the ground. This is an effect induced by her dialogue with the earth’s gravity: to manipulate this brush, which has become very heavy, she supports it with a cable and attaches a bicycle handlebar to it. She can then change direction by making it turn on itself at a point around the vertical.
A physicist looks at Fabienne Verdier
Straight line with its starting and stopping point, repetition to infinity thanks to the back and forth, curvature of this same line, then rotation and change of scale. As a physicist, I see in it the elements that allow us to deploy an “abstract language around a constant movement”. The infinite combination of these elements is of immense richness and invites us to pay renewed attention to our movements and to how the world is changing around us.
