This sculpture uses three servo motors and an ir sensor which detects objects a few feet out.  The three sculptures, all scaled versions of each other, display an open, oscillating behavior when the sensor is not detecting any object close to the sculpture.  When someone or something approaches the front of the sculpture the spirals hide in their nested state.

Each spiral is made of laser cut hard board and paper.  The spirals use a single gear/link that is scaled and copied.  Each link meshes with another link that has been scaled by the scaling factor (in this case .8) squared.  The link that has only been scaled once acts as the base for the first and .8 squared link. Sorry if thats a bit convoluted.  Basically the gears serve the purpose of making the angle between each pair of links the same.  Add scaling to the series of links and a log spiral is created.  As opposed to many spiraling kinetic sculpture that unfurl sequentially (in the maner of ferns) the spirals maintaing the log spiral constantly because of the gears.  The next step is either a giant version that can be set in motion by hand and oscillates because of balance, or a branching fractal that opens and closes.

The paper units are also one single shape being copied and scaled.  The base unit was modeled in a 3d modeling program (Blender) and then unwrapped using pepakura.  Unwrapping consists of determinging which edges will act as seams and the pepakura software adds tabs where necessary.  the unwrapped sculptures (nets) where then cut on a laser cutter and glued by hand. It took me forever.