The great Sol LeWitt died on Sunday. He might be best known as a sculptor, but like many people I most admire his “Wall Drawings,” a series that he started in 1968 and continued, as far as I know, to the end of his life.

The wall drawings are drawings done directly on walls, which raises the immediate question of portability. These days (i.e., since the 17th century or so) we’re used to art being primarily something that comes as discrete objects, usually small enough to be portable (even if you have to hire some art movers to move it for you). The nice thing about smallish, discrete art objects is that you can easily buy and sell them and transfer them to the residence (or exhibition hall) of the new owner. But it’s easy to forget that, for centuries, art was primarily largish and non-portable: frescoes, altarpieces, marble reliefs, cave drawings.

LeWitt didn’t operate outside the art-world economy made possible by portable works, though. No artist can. LeWitt’s wall drawings were portable despite being done directly on the wall because of another feature — the constitutive feature of LeWitt’s work, actually: that he didn’t execute the drawings himself. He wrote instructions, sometimes detailed, sometimes not very, and the drawings were carried out by other artists or art students. When a piece was sold, the drawing on the wall was painted over and another crew had to be hired to execute it in its new location.

I started my description of the wall drawings with a discussion of how they fit in the buying and selling of art because I’ve always been fascinated with how these pieces interrupt the charade of private ownership of art. LeWitt made plenty of money over the course of his career, some from the sale of more traditionally portable pieces — sculpture, paintings and drawings on paper, prints — but some from the sale of wall drawings.

One of his wall drawings, #6-A, sold for $114,000 earlier this year at Christie’s. The auction database I’m using shows a picture of the drawing as executed, along with smaller, hard-to-make-out photos of two key documents: the instructions (which in this case include a diagram of the finished drawing) and a signed certificate of authenticity.

The certificate of authenticity suggests a certain ontology of the wall drawings: that each exists in at most one executed form and that each real wall drawing must have a corresponding certificate of authenticity filed away somewhere, like an elevator inspection certificate. This ontology supports the practice of buying and selling LeWitt wall drawings, since it creates scarcity — in fact, the particular kind of scarcity, “uniqueness,” that is best for art prices.

As opposed to this official ontology, though, it’s easy to imagine a more permissive one: there is no limit to the number of executed versions of a single wall drawing that can exist concurrently, and a wall drawing is certified not by being notionally attached to a signed certificate of authenticity but by being executed in accordance with the instructions.

The permissive ontology of wall drawings has many benefits, but I’ll just mention two. First, it exposes the magical thinking involved in the buying and selling of art, the strange notion that a thing is better because it was touched by a famous artist rather than an anonymous craftsman or a robot. (I’ll leave it to the reader to continue this through to Marx’s commodity fetishism.) Second and relatedly, it questions whether people really like LeWitt’s wall drawings or just pay lip service to them — if you can have one in your home for the cost of a couple day’s labor and some art supplies, why don’t you?

(I have a plan to produce a series of instructional books and videos, to be sold at Home Depot, for making your own Donald Judd plywood boxes. I once had the opportunity to mention this idea to a prominent New York gallerist, who thought it sounded great and told me about a neighbor of hers who had made his own Felix Gonzalez-Torres light sculpture. A whole generation or two of artists are vulnerable to this kind of thing; only mad skillz in the studio can save you from mass reproducibility.)

Besides all that, though, remains the core issue of rule-following. LeWitt was interested in Wittgenstein and the indeterminacy of rules. I understand that LeWitt often supervised or at least approved the result of a crew’s execution of his drawings, but he also left plenty to chance and to the interpretation of the executors. Kriston Capps wonders, “We have his instructions and descriptions, and I would imagine some were never executed. Do we still have his work?” I’d add other questions, following Michael Kimmelman’s comparison of LeWitt with a composer whose music is played by others: Without LeWitt around, will the execution of his wall drawings drift from the current canon? Can we look forward to a spate of revisionist LeWitt installations, followed by a ferocious movement (led by top academics) to return to “drawings as the artist might have envisioned them, if he had envisioned them,” done with “period art materials” on “period surfaces”?

One of my favorite wall drawings is one of the first ones I saw, at a small but erudite LeWitt show at Reed College in 1998. Drawing #123 was executed for the show by Reed College students. The instructions are as follows:

The first draftsman draws a not straight vertical line as long as possible. The second draftsman draws a line next to the first one, trying to copy it. The third draftsman does the same, as do as many draftsmen as possible. Then the first draftsman, followed by the others, copies the last line until both ends of the wall are reached.

The final drawing is exquisite in an austere, early-conceptual way. Each line is a little less straight than the preceding one, so ripples appear and become more exaggerated as you look across the drawing from oldest to newest line, like contours on a topographical map. The regular variations unfold as the result of human failing: it makes the arm ache to draw a line from the top of a wall to the bottom, following but not touching the line next to it. But the result has a spontaneous organization of great beauty.

I once had a version of this drawing going on a large piece of paperboard in my office in grad school, but it really deserves its own wall. I intend to give it one as soon as I have a blank wall that can hold it, although I can’t seem to find a certificate of authenticity around here anyplace.