When I was a kid my Aunt Betsy, a designer, had a drawing of bottles hanging on her wall.

“What does it mean?” I asked.

“It’s just a study,” she replied.

“But,” I nodded, “what does it mean?”

Art history 101: not every piece is a puzzle waiting to be solved. Consider one of Jasper Johns’s best-known images, now on view at the Walker Art Center in the form of both a painting (Flags, 1965) and a related print (Flags, 1967-68). An American flag appears in negative view, so if you stare straight at it and then at a blank rectangle (helpfully provided), the afterimage on your retina provides a fleeting view of the flag in its conventional color scheme.

The work dates to the era of Vietnam and the Civil Rights Movement, but Johns never suggested any political associations or implications. In a large exhibit of the artist’s prints, curated by the Walker Art Center and now returned to the Minneapolis museum after opening in Pittsburgh, the Flags hang near contemporary takes on numerals and shooting targets. What does it mean?

Accessible yet inscrutable: if that sounds like Andy-one else you know, that’s no coincidence. As curator Joan Rothfuss explained on a Thursday morning media tour of the show, Johns was a bridge between abstract expressionism and pop art. His work marries the expressionists’ interest in textures and systems with a willingness to repurpose found images that served as both an invitation and a trap.

The eye is immediately drawn to the work, trained to look for meaning and context, only to discover that the latter is detached and the the former is vacant. Once you’re engaged with a piece, though, you discover perceptual layers — like the bands of hue that roll systematically over the numerals in Color Number Series (1969). After decades of study, Rothfuss said, she only recently noticed the detail that Johns signed his name on each print in that series in a color matching the top of the respective image.

“I see the artist isn’t here,” said one attendee on Thursday morning.

“He’s dead,” explained another.

He’s not, actually. As the exhibit illustrates, Johns is still working at age 89 — and still sending a copy of every one of his prints to the Walker, ensuring the institution’s collection remains complete. The current show, An Art of Changes, traces the artist’s career from those epochal early works through to his most recent work: based on imagery that keys to his earlier pieces, to mortality, and to a unique type of self-portraiture. Johns and his own work, now, have become founts of found images.

The show offers other opportunities to compare the artist’s painting and sculpture to his printmaking; notably in the case of Fool’s House (1962), an canvas adorned with oil paint as well as everyday studio objects like a broom and a cup. Walking through the show leaves you with a new appreciation of the sweep (so to speak) of the artist’s career as well as his incredible sensitivity to the qualities of our visual world that are often (here we go again) overlooked.

Two of his major motifs represented here, for example, were spotted on drives around New York City. Few Gotham traffic jams can ever have been as productive as the one in the ’70s that acquainted Johns with the crosshatch pattern that became the basis of Scent (1975-76), Cicada (1979-81), and numerous related works.

It’s work a student of visual perception can love, and occasionally — as in Untitled (1988) — Johns incorporates visual illusions that show how the brain can fool the eye into seeing something that’s not there. More commonly, the artist’s oeuvre suggests, we make the mistake of missing so much that is there. We typically don’t notice it, but Johns, it seems, notices everything.

– Jay Gabler