Our own Morgan Meis in The Smart Set:
Sol LeWitt was fond of cubes. Sometimes, he would make sculptures that were nothing but cubes, cubes within cubes upon cubes. In the early 1970s, LeWitt produced works like “Cube Structures Based on Five Modules.” The title captures the essence of the work. LeWitt took a bunch of open cubes made of wood, painted them white, and arranged them in various geometric structures. He just liked the cubiness of cubes.
This led a number of critics to think of LeWitt as a formalist. All the geometry spoke for itself. This was an artist of Cartesian spaces and strict rationalism. LeWitt was showing us something about the austere beauty of form. His white lattices were supposed to be an abstract representation of Mind itself, the way principles of thought progress from root axioms to logically deduced conclusions.
It took the great art critic Rosalind Krauss to notice that there was a madness in all these cubes. Why, wondered Rosalind, can't you stop this manic proliferation of cubes, Mr. LeWitt? It was a good question. A couple of cubes here and there might make a fair, if boring, point about form. But LeWitt was obsessed. Here's what Krauss said in an essay about LeWitt in her epochal The Originality of the Avant-Garde and Other Modernist Myths:
Like most of LeWitt's work, “Variations of Incomplete Open Cubes” provides one with an experience that is obsessional in kind. On the vast platform, too splayed to be taken in at a glance, the 122 neat little fragmented frames, all meticulously painted white, sit in regimented but meaningless lines, the demonstration of a kind of mad obstinacy.
More here.