Mass MoCA offers an answer to my question of how a manual generative process works. Embedded in a generative process is the idea that there can be multiple results that derive from the same rules and initial framework. Sol LeWitt's art is an art of ideas. His work is not about the visual outcome but rather about the idea and process behind the art. "A Wall Drawing Retrospective" is a series of wall drawings/paintings that were produced from a description by LeWitt of a concise idea and diagram. The wall drawings are not actually produced by LeWitt himself but rather by others.
The idea is described almost like a series of instructions and relationships between elements and is accompanied by a small hand drawn diagram. For example for "Wall Drawing 797" the instructions state:
The first drafter has a black marker and makes an irregular horizontal line near the top of the wall. Then the second drafter tries to copy it (without touching it) using a red marker. The third drafter does the same, using a yellow marker. The fourth drafter does the same using a blue marker. Then the second drafter followed by the third and fourth copies the last line drawn until the bottom of the wall is reached.
Here are some images of the results:
Photo: Will Reynolds, www.massmoca.org
Photo: Cortney, intern @ www.massmoca.org
This simple idea of "copy-line" produces something that reveals subtle complexities throughout the piece. This is where I came to understand the idea of manual generative processes. This piece can be produced multiple times and never yield the same result. The simple rules are able to generate complexity. The "copy-line" in this piece shows similar results to the "offset" command in Rhino where the line changes and deforms with each offset. This is what shifts the curves in the initial line to more jagged lines in the progression.
Not all LeWitt's pieces have the ability to produce such complexity nor are they a generative process that will yield different results. I prefer the pieces that seem more indeterminate. I find them more interesting because of the effect the simple rules have produced. I also like the idea that the piece could be repeated and yield something different but within the same level of complexity.
Mass MoCA has a nice website showcasing the Sol LeWitt A Wall Drawing Retrospective but it definitely is not the same as being there.