When we discuss Systems Art, the very term itself is often the subject of disagreement. What do artist's mean when they refer to art as being systematic?
They might mean geometric, or minimal, or reductive, or developed by following rules, or by the application of an obvious Process.
It is too narrow, I think, to confine the use of the term Systems to its use in cybernetics to focus on feedback.
In general, what is meant is that the art is Systematic. That there are clear rules that have been followed in its construction, even if these rules are not obvious to the observer.
Let us take the term Systematic as the key to understanding Systems Art, or indeed all art from a Systems viewpoint.
Although Sol Le Witt wasn't happy to have his work classified in this way, much of his work is geometric and as a consequence systematic. One aspect of some of his work was that it was conceptual. It was the concept or the idea that was the art, not its realisation on the canvas (or wall, often as not). Le Witt wrote out instructions, which when followed would realise an instance of his work (which he might then certify).
This use of written instructions is clearly systematic.
It is very musical. In conventional music, the composer writes a score and instructions, the performers realise the piece by adding their own interpretation. In indeterminate forms (Cage) or improvisation (Jazz) the division between composer and performer shifts toward the performer. So too with Le Witt's conceptual art. The realisation has the essence of Le Witt with the interpretation of the performers (usually a group of artists).
The use of written instructions corresponds to our more contemporary us of computer programs or Algorithms or other mechanised processes.
Which brings me to Reverse Conceptual Art.
Much of art, when we look at it, speaks to us immediately of the processes by which it was formed. This is how the artist communicates meaning to us. We may look at the work (or listen to it, or watch it) in wonder, or in incredulity, or on shock, or in indifference. But something has been communicated.
We look at the work and try to appreciate the systems which constructed it. We try to reverse-engineer the concept which formed it. We try to write the instructions that a conceptual artist would have written in order that we could realise their work in their absence.