Joan Truckenbrod, Coded Algorithmic Drawings, 1975

Joan Truckenbrod: When I started, I really was interested in making an impression or an image of invisible forces in the natural world that were palpable but invisible. I wasn't really interested in drawing them, or painting them, or photographing them. I was more interested in an expression, or an experience, or an impression of them. Then it became obvious that I could make a mark with a computer.

But I then discovered that there were in fact mathematical formulas that described some of these phenomena so I could develop algorithms using these algebraic formulas and then integrate them into computer programs so that I created usually a series of images. Sometimes the series were drawn out in a linear way, like one at a time, and the text style was done in that way. Or sometimes, the series or the sequence would be superimposed on one another, so you'd get the sense of motion and depth that expressed that series, sort of the trajectory. I always think of nature as not being still, but that there's a trajectory, that they play out, like growth patterns or light waves undulating or wind currents moving, things like the series of leaves on a particular tree.

I tried to express that through programming.