The first iteration of the machine involved a computer fan hung from the ceiling by its own power cord. Suspended from the fan was a long piece of string with a marker on the end. As the fan blew itself around, it dragged the marker across a large white sheet of paper I laid on the floor. Occasionally the marker would violently bounce off of people or things. When the machine ran, I typically sat out in the hallway on a folding chair with my laptop and waited patiently. A typical drawing took about 30 minutes to an hour (even with a couple of marker changes).
I mounted and hung drawings from the first round in my studio space's art gallery without permission. A silly sign was created.
The second iteration involved two fans. There was the original fan and then a few feet away was a second smaller fan that was hung closer to the ceiling (hence, with a shorter traveling range). The string was suspended from the new fan through a hole in the old fan and then to the floor. This resulted in the new fan tugging at the old fan and adding a wee bit of randomness to the drawings.
I tried selling the drawings created by the second iteration for $500,000 a piece during one of the studio space's open houses. This did not succeed. I ended up cutting up most of the drawings and using them as wrapping paper.
A few of the remaining drawings were framed. One had a snide cartoon posted on it and was subsequently mounted in my living room.