Glass is a visual and sensory exploration of the boundary between the quantum and classical worlds. Two levels of reality, which for us are vastly separated in scale, are brought close together so that they may be perceived simultaneously. 

To experience Glass you must look at its microscopic world.

Panes of transparent glass intersect and overlap. Starting anywhere, you can interpret what you see as part of a three dimensional object, but whose orientation is unclear. As your eyes continue along a path, you will find edges that force the panes to take a specific orientation. But if you try to extrapolate, you find contradictions: panes that looked horizontal now seem to be vertical, or vice versa. On a larger scale, it is impossible to perceive this scene as a definite physical object that can live in three dimensions. 

Remarkably, what you are experiencing maps onto a typical quantum mechanical system, like our universe. In a modern extension of the Copenhagen interpretation of quantum mechanics*, the characteristic feature of quantum reality is that different observers can have inconsistent histories about what happens in the world. There is fundamentally no single objective reality on which all observers will agree.** 

Glass is based on the premise that while here, the top group of panes looks vertical and the bottom group looks horizontal, ...

... if we see only a small subset of these clusters, we cannot distinguish them.

So the two states exist in superposition, until we reach an edge, where typically one particular orientation is favoured. This represents a measurement in quantum mechanics: the collapse of the wave function.

* The Consistent Histories Interpretation, proposed by R.B. Griffiths (1984) and elucidated by the late Pierre Hohenberg in his Reviews of Modern Physics article (2009).

** This statement is shared by all interpretations of quantum mechanics.

The degree to which this effect is present varies from piece to piece. Those with the Ziggurat feature look highly coherent and therefore highly entangled, in the quantum interpretation.

Those with Waves show structure at the larger scales, representing the classical domain where indeed what we typically measure are waves.

( These effects can coexist, as here )

In contrast, those without any Shadow and without Flow are typically the most ambiguous.

Yet when we zoom out, we can appreciate a harmonious whole. This represents the classical world to which we are accustomed. Its apparent solidity depends on our not looking too closely.