THE WALKER ROCK GARDEN is a curious, fantastic zone, the wildest backyard in town. The visitor inevitably gets lost in the garden's minutiae and restless patterns made from thousands of rocks. If you've ever been subjected to a Rorschach test, you may recall that experience in this place -- minus the sneering psychologist -- because, in treading and retreading the garden's walkways, you invariably find new details and pictures in the stones each time.

This small dreamland in West Seattle is one of those off-the-map institutions that exists outside visible local culture. Clichéd sorts of questions -- Is it art? What kind of art? -- tend to come up in the catalogues, articles, and guidebook pieces that have documented the garden, because the garden's creator, Milton Walker, was a self-taught artist. But academic questions about classifying the work as art, craft, kitsch, art brut, or other fall away when you see the place, because the garden, like a dream, presents itself wholly on its own terms, and defies easy description.

Walker, who died of Alzheimer's in 1984, wanted to create a tribute to nature, says his widow, Florence. At age 90 she remains in the house where she and her husband moved in 1939. In 1959, he decided to make an imitation lake in his backyard, and was apparently unhappy with the outcome; he began to embellish it with rocks, and the garden took off from there. For 20 years he continued this project, and today the yard reveals the intensity of his vision and work. During winters, he collected and sorted new rocks; springs and summers, he added these to the garden, building the place up like a nest.

The garden was like an organism its creator depended upon. "He was always working on it, every weekend," Mrs. Walker says of the former Boeing machinist. Entering through a gate alongside the Walkers' modest cottage-style house, you look across a landscape of mountains (caps painted white), pathways, slopes, and miniature lakes; looking closer, you see that everything here is entirely made of rock, mosaic-style. Bevies of ovoid river rocks line the walkways in rows; red, blue, turquoise, and green semi-precious rock and glass bits are embedded in the structures. Curved doorframes, walls, arches, niches, steps, jagged hillsides, and an 18-foot tower sit behind the plain suburban cottage; the miniature lakes and stream beds (painted blue inside, filled with water) are meticulously lined with unending rows of rocks; stare long enough and they look like liquid. Crystal-lined hollow spherical rocks called thunder eggs abound; jewel-like stones also cover every crevice and ledge. The effect is staggering. Even the path beneath your feet is lined with smooth, caramel-colored petrified wood. This tribute to nature does not, of course, look "real"; its neatest virtue is that it looks hyperreal. As in Candy Land, everything is made of the same stuff, suggesting that the world and its contents are all-one, unified -- which is true, in a way, and in another way, it's not true.

Over time, word about the garden spread. At first, neighbors and friends came to look; then people began calling for appointments; last year on Mother's Day, about 200 people made their way here. One article suggested that the high tower in the back yard bears a striking resemblance to work by Spanish architect Antonio GaudĂ­. "Milton was born in Eastern Washington, and he never heard of GaudĂ­," Mrs. Walker says. "He just had natural talent, and he never knew he had it until he started making the garden."

With the sun bearing down, and algae floating in fragile lakes below miniature mountains, the place seems lost in time. The presence of memory is strong here; a photo of Walker sits propped on a picnic table under a patio adorned by rock. No one is around, and the sound of highway traffic filters into the backyard, a reminder that a world of commerce and prosperity is hurtling around us. As he labored alone in this garden in the 1970s, Walker could hardly have anticipated this world of money upon money that relegates a curious time machine like the rock garden to the silence of its own history, like a cipher.

Visitors keep Mrs. Walker busy, and she insists that the garden keep its original spirit and intention -- that it remain free of charge for anyone who wants to see it. She tries to explain her husband's motivation: "He was trying to make it like nature, and nature is heaven, I guess. He worked on it all the time, on all the weekends." From the crevices of memory, she recalls days when she would help her husband. "We'd go spend weekends picking up river rocks, sorta everyday rocks at the Columbia River. We'd spend the night there, and I'd have a pail. Then Milton noticed yellow rocks around there. I helped him collect them, and they turned out to be petrified wood. In those days you could bring home as much as you liked."

"We want nothing commercial about it," says Sandy Adams, the Walkers' daughter, who lives in the house and helps her mother manage the garden. "We don't want to advertise. Word of mouth is fine. If I see something highly advertised, I stay away. A lot of ads means there's something wrong." Ms. Adams' words are fresh and stark in a city that is more than ever about the urgent exercises of selling.

Of her father, Ms. Adams recalls, "I don't think Dad fully understood that most people couldn't do what he did in our backyard." Mrs. Walker implores all garden visitors to sign a guest book in her living room. She tells me to stay in the back yard until the light of day ends. It's chilly in her house, and I advise her to keep her windows shut tonight. From her kitchen window, she can look out upon the complicated, panoramic garden, whose odd and deliberate beauty points to the past and even retains it.

She recalls her husband: "He was a wonderful person. I was a lucky person to have him as a husband. I didn't realize how lucky I was until I heard people on TV," she says, referring to shows like Jerry Springer. "I just want the original spirit of the garden to be kept, and not charge anyone to come here," she repeats. She repeats this often, as if prompted by the memory of her husband. Her private memories, and the garden of thousands of rocks -- this homage to mountain lakes, and to rocks themselves -- settle in for the night. Perhaps Mrs. Walker is lucky or, like most people, both lucky and unlucky. In any case, she has lived to age 90, and has a silent, stone remembrance of her life to think about each morning as she stares out the kitchen window.

The Walker Rock Garden in West Seattle is open by appointment; call 935-3036 for a reservation.