Tension and Balance,

are the two words that sprang to mind,

 when I first looked at this glass dome, 

 the sculptures each include a rock suspended within a glass enclosure,

 the rock’s weight perfectly balanced by the mechanisms, systems, and pulleys that surround it, keeping the rock in midair, 

 the sculptures are the work of Dan Grayber, “Cavity Mechanism #6, from 2009, [seen below] is one of the most obvious pieces to speak about interpersonal relationships that I’ve made,” said Grayber toVenison Magazine, “There are two identical mechanisms inside of a glass display dome, and one small cable that runs between the two mechanisms. This cable holds all of the tension between the two mechanisms, and they both need to remain in place to maintain the tension. I was really thinking about co-dependence when I made the piece. If either mechanism were to slip, or the connection between them to break, it would cause both to fail.”

trying to work out the mathematics of stresses, loading's and all of the other parameters in these works is giving me a headache!

 but how neat that the pulleys and other systems balance everything just so, You can see more of Grayber’s experiments in equilibrium on his Instagram and Facebook pages, amazing.