Morphogen

What you are looking at is alive, in its own way. It is a living tissue, a sheet of cells, growing under a microscope as you watch.

It is generated live, by code. Every cell is simulated, one by one, inside the work, and the body you see is the work of all of them together.

The cells

The organism is made of about thirty thousand cells. Each one is simulated as a point with a direction: a top and a bottom, as the cells that line our own skin and gut have.

Two cells hold on to each other only side by side. Placed one above the other, they push apart. From this single rule, the cells arrange themselves into a sheet, one cell thick, that bends and folds and stays one cell thick.

The chemistry

Through the sheet runs a chemistry. Two substances pass from cell to cell through their contacts. One feeds on the other, and the other spreads faster.

In 1952, Alan Turing showed that such a pair can draw patterns by itself: spots, stripes and labyrinths. He called these substances morphogens, the makers of form. The work takes its name from them.

The shape

Here, the pattern does more than colour the tissue. Where the chemistry is active, cells grow and divide, and each one narrows slightly at the top, the way cells bend the body of an embryo. There, the sheet rises into domes, ridges and corals.

The pattern shapes the body, and the growing body carries the pattern with it, stretching it, splitting it, and setting it in motion again.

The grains of light

Each cell is drawn the way a super-resolution microscope draws one: as grains of light, one for each glowing molecule.

About a hundred belong to every cell. They trace its membrane, gather in its nucleus, and run along the fine hair on its surface, which beats in waves across the tissue. Half a million grains are placed sixty times a second. Together, they are the image.

Under the lens

We look down on the tissue from above, through the lens. Its focus is shallow: only one depth is sharp at a time, and as the focus drifts, it travels through the body, from the crests of the domes down into the folds between them.

The lens has flaws, as real lenses do. At the edges, colour separates a little, and the field of sharpness is slightly curved.

Waves

Every cell can be excited, and it passes its excitement to the cells it touches. Then it rests for a while.

So waves of activity cross the tissue as bands of light, the way waves of calcium cross our own tissues. A cell that the wave reaches turns to crawl toward where it came from. Slowly, the whole sheet answers.

Life and death

Look closer, and you can follow single cells. A cell that has grown divides in two, in the plane of the sheet. Where the tissue is crowded, a cell is pushed out of it: it flares as it dies, rises toward the lens, falls out of focus, and dissolves.

The number of cells stays near a balance, held by what the medium can feed. Each cell lives for a while. The organism goes on.

One body into the next

The two rates of the chemistry drift slowly, along a path set by the seed, through the regions where this chemistry can live: spots that divide like cells, worms, coral and labyrinths.

As they drift, the organism turns from one body into another. The path is endless and always new. What lies under the lens now is growing for the first time.