Figure #5 and 6: Spines
Two units of different sizes.
Each of these figures consists of an elongated transparent "plastic bag" with a spine-like structure inside. The spine structure's zigzag shape is somewhat reminiscent of the bellow of an accordion but much narrower. The internal construction is somewhat reminiscent of the human spine. Below the spine hangs a box containing electronics from which a thin black plastic pipe emerges, falling almost to the floor before making its way up to the top of the "spinebag". The figure is, in fact, nothing more than an actuator. It works by using a small electric vacuum pump and some solenoid valves to pump out the air from the bag surrounding the "spine". Since the spine is made up of rectangular pieces of plastic connected with pivot joints, the spine contracts to shorten the whole structure's length as the air is sucked out of the bag. Both of these figures can contract more than 2/3 of their total length.
They are suspended from the ceiling using copper wire, and thus even if their primary movement is only to contract horizontally, this action does create a rotational movement caused by the torque of the vacuum pump as it changes speed. Since the wire from which the figures are suspended is so compliant, and the pump spins quite fast, this is enough to cause a significant rotational excitation.
The mechanism that drives these figures also creates sound. The largest of the two spines has a larger pump creating a somewhat low pitched but audible tone with the frequency changing with the pump's speed. The smaller of the two spines has a smaller pump that runs faster, creating a tone that is quite a bit louder and at a higher frequency. The airflow to and from the plastic bag that surrounds the central structure is controlled using solenoid valves. As most solenoids, these create an audible click as they engage and disengage. Each of the figures has two valves allowing the figure to keep the vacuum in the bag without running the pump, in effect "holding its breath". The power supply is connected to the figures using copper enamel wire that hangs freely down to the floor, further accentuating the figure's movements.
Impetus
Figures #5 and #6 have no limbs. The other figures have generally emerged as mechanisms that manipulate what could be construed as limbs. This is not the case with figure #5 and #6. They seem to me to be structures that are internal somehow. The association I have with them, one I have come to understand is shared by many audience members, is that they are breathing or being lung-like. They are clearly machines, but because their activity is only to seemingly draw their breath and exhale, they seem somewhat organic to me. My pursuit of fluid or gas-driven actuators such as the ones employed here was motivated by my own association with manipulating fluids and gases as somehow being reminiscent of the organic processes I am familiar with within my own body.