In the past 10 years or so I have largely focused on building machines which are themselves pieces of art. When I first started, stepper motors, drivers, and computers were too expensive and rare for me to think of creating kinetic pieces. Now, thanks to computer speeds and eBay, I am able to create pieces which explore motion control in ways that no kinetic piece could.
For example, in my Sisyphus series, I use a 2-axis machine to slowly roll a ball through sand to make complex patterns requiring many hours. Animanemone is a different approach: here I used 7 x 7 x 7 = 343 stepper motors in an array like a sea anemonone to create life-like interesting motion.
In my mind, every kinetic piece is like a musical instrument. I have been able to create the machines, but now I am working on creating algorithmic paths (music) to really create the effect.