Working for the late conceptual artist Sol LeWitt can be rigorously putzy. Four artists installing Walker Art Center's new LeWitt show spent a whole day doing nothing but sharpening thin rods of lead and colored pigments, like pencils without their casings. After sanding two gallery walls and coating them with special white paint, the crew spent another day masking them with tape. Then they got out long, wide rulers and began drawing faint criss-crossing lines on the walls about 1/8 inch apart in various colors -- black, red, blue, yellow.

"There's an ebb and flow of boredom, excitement and fear," said Chip Allen, a wall-drawer who has worked for LeWitt's estate since graduating from Rutgers University three years ago. Pausing to reconsider, he amended that. "Well, no, you don't actually get bored. It's relaxing and kind of meditative to draw the lines."

To aficionados of conceptual art, that's a fair description of LeWitt's mostly geometric prints, sculptures, wall drawings and other art: serene, meditative, minimal and all wrapped up in brain work. More than 100 LeWitt pieces are on view in the Walker's new "2D + 3D" show, which surveys the Connecticut artist's career from his earliest 1960s white-painted wooden cubes to the last eye-searing explosions of gaudy lines. It includes a video of a Lucinda Childs dance performance for which a film by LeWitt served as a projected set. All of the art is owned by the Walker, a favorite museum to which LeWitt (1928-2007) often gave samples of his work.

"Things would just arrive from him unannounced," said curator Siri Engberg, who organized the Walker show and remembers unpacking some of his surprise packages. With its gridded, white terrazzo floors and ornament-free walls (no cornices, woodwork, sconces or other fancy stuff), the Walker's 1971 brick building was a particularly happy home for LeWitt's work. For years his huge stack of open cubes stood on the Walker's rooftop terrace, the sculpture's boxy white frame a perfect advertisement for the minimalist art inside. Now Engberg has moved the 14-foot-tall sculpture inside, where it looks like the framework for a gigantic playhouse. There's another LeWitt piece -- a huge columnar sculpture made of concrete blocks -- in the Minneapolis Sculpture Garden.

One of his room-sized wall drawings also can be found in the museum's former restaurant in a brutally insensitive mismatch of art and architecture that, unfortunately, ruins the proportions of both and turns a previously beautiful room into a gloomy cavern. That 1984 drawing, consisting of huge blue geometric shapes (circle, square, parallelogram) edged in gold on terra cotta walls, was commissioned for a smaller lobby gallery suited to its colors and proportions. LeWitt apparently gave his approval for the relocation, but the results are ugly.

Geometry with soul

After graduating from Syracuse University and serving in the Korean War, LeWitt came of age professionally at a time when Abstract Expressionism dominated the American art scene. Driven by philosophical musing, arty personalities and gestural color, AbEx was a mode with which LeWitt had no sympathy. Famously self-effacing, he avoided being photographed and devised ways to make art from the simplest of means: a cube, a line, some basic colors.

At first he fashioned his sculptures and drawings himself, but later he conceived the notion of writing descriptions to be executed by others. Sometimes the instructions are even included in the drawings or prints, where they read like strange little haikus. A print from the early 1970s consisting of many rows of softly colored squares includes the instruction that it represents: "all one two three and four part combinations of lines in four directions and in four colors." Another exercise generated 64 colorful silkscreens from "straight, not-straight and broken lines using all combinations of black, white, yellow, red and blue, for lines and intervals."

"Language was as important as the lines to him, and the words really do become a type of poetry," Engberg said. The words were also a strangely specific code, she said. A "not-straight" line was not the same as a wavy line, for example.

Organized in a loose chronology, the Walker's show starts with primarily monochromatic work -- honeycomb arrangements of cubes and drawings of simple shapes that become increasingly complex and engaging as he explores their permutations. In the 1980s he moved to Spoleto, Italy, where his exposure to frescoes led to an explosion of color and a new lyricism. The Walker's show includes a suite of moody geometric prints in muted bronze, plum, teal and gold that, in a fanciful reading, might echo the autumnal hues of the Umbrian countryside. Rainbow arcs explode from other works, and by 2000 he was using what he called "loopy doopy" lines in eye-popping combinations of electric blue and red.

Sachi Cho, who worked for the artist and since then for his estate for the past 16 years, said she was influenced not only by LeWitt's art but by his way of life. "He was, I can't describe, he was like an angel," she said, during a break from work on a wall drawing. "He was famous and well known, but he was always quiet and humble and never wanted to be the center of anything." • 612-673-4431