The digital screen is a matrix of dots, each of which can be controlled for a limited range of parameters, how red, how green, how blue, how bright. When added together in very large numbers, these elements can form an endless variety of pictures-they are picture elements, pix-els, pixels.

Imagine a building made of bricks. Now imagine each brick to be a pixel. We could vary the colour, we could vary the texture, we could vary the spacing, or how far from the surface of the wall each brick protrudes or recedes. Imagined this way the wall becomes a surface full of possibilities.

Everything we make a building from can be thought of in the same way, as a part of a larger whole, quite limited in its variations, and constrained too in the ways in which it can be joined to other pieces. If we make the effort to understand these rules, and to understand how much room each full offers for play, every wall, every building can find its own freedom to be itself, a little different to the others, adding up to a more interesting world.