Just two years ago Sandra Garratt was cleaning kitchen floors and scrubbing toilet bowls for $5 an hour. This year she's cleaning up in a bigger way—with a projected $1 million in royalties as the designer of Multiples, a line of mix-and-match clothing that is rattling the racks in about 600 stores across the country. Garratt's threads will pull in an estimated $110 million in sales this year for Jerell Inc., the Dallas-based firm that bankrolled the designs, and company president Jerry Frankel sees bigger days ahead. "Multiples is growing like Reebok did," exults Frankel, a rag-trade veteran. "It's not just style, it's concept."

Garratt's unisex, one-size-fits-all clothing consists of 22 pieces, including jumpsuits, coats, turbans, tube tops, leggings and headbands. Square cut like surgical scrubs, the cotton-and-polyester garments can be layered, rolled, tied, turned upside down or inside out and transformed in dozens of ways. The tube triples as a short skirt, a sash or a body-clinging top. The stretchy leggings can be worn on the arms, as well as tied around the waist.

With single units of Multiples selling for about $21, the clothes have found a ready market with teens, working women and anyone with a little imagination. "The best thing about them is that there are no rules, no right and wrong," says Suzy Stewart, a vice-president of Bloomingdale's. "Women can easily achieve whatever look they want—sexy, glitzy, understated."

For Garratt, 36, just looking successful is satisfying enough. Eight years ago she was divorced, living in Dallas and struggling to support her infant son. Then she spent the last $38 from an unemployment check and bought some fabric. She sewed a small collection of shirts, pants and skirts that could be combined in various ways, called them modulars and displayed her samples at some local boutiques. In a matter of weeks, the stuff was hotter than a Dallas summer.

More adept at fashion than finance, Garratt soon had to contend with a growing payroll and a backlog of work. In need of capital for her fledgling company, known as Units, she hooked up with a group of local businessmen in early 1986. The partnership lasted less than four months before the designer and her bottom-line-minded backers were locked in a series of disputes. Garratt sold her share of the company to pay off her debts and agreed in writing to stay out of the Dallas fashion business for six months—time enough to give her erstwhile patrons a head start in securing her market. Frustrated, she went to work as a housekeeper and bided her time. "I felt like a lion who had tracked down an antelope," she says, "and then watched the jackals rush in."

Last year, with backing from Frankel, Garratt was back in business and running hard. New Multiples outlets are now opening in stores at the rate of 25 per week, and workers are sewing about 10 square city blocks of fabric every day to keep up with orders.

Her latent fashion skills notwithstanding, Garratt's passion as a child was dance, not design. The daughter of an English mother and a Scottish father, she was born Sandra Harrower in South Milwaukee, Wis., and moved near Malibu, Calif., after her father took an aerospace job with Lockheed. She sewed her own dresses as a teenager and once was sent home from school for wearing a too-mini mini of her own creation. But her future, she thought, was in tutus, and after winning a scholarship to Canada's Royal Winnipeg Ballet School, she toured Europe with several dancing troupes when she was 19. Calcium deposits in her ankles abruptly ended her career, and after a string of odd jobs, Garratt enrolled at the Fashion Institute of Design and Merchandising in L.A. It was there, while working on a school project, that she hatched the idea for mix-and-match, all-purpose clothes.

The idea simmered for almost a decade. In the meantime she moved to New York, married Michael Garratt, a textile designer, and settled into some low-paying, girl Friday jobs with designers, including Mary McFadden, Zoran and Halston. One night she looked in a store window and spotted a display of disposable Bic lighters. "I wish I'd thought of that," she remembers thinking. "Everybody can afford one. If you give people something good and cheap, you could make a zillion dollars." A few years later in Dallas, after her two-year marriage had foundered, she set out to do just that.

Garratt's success since then has had surprisingly little impact on her life-style. She and her son, Wesley, now 10, live in the same brick warehouse building that has served as her office for the past two years. File cabinets double as room dividers, a hot plate suffices for cooking, and a couch used for staff meetings by day doubles as Garratt's bed for the night. Still friends with her former husband, a manager of a Dallas clothing store, Garratt is dating architect Lawrence Cosby, 34, who moonlights as a rock guitarist for a local band called the Obscene Limousine.

Competition with her old company, now known as Stinu—Units spelled backwards—is fierce. But armed with a new line of Multiples for children, Garratt is already doing business in Europe and will soon be moving into Australia and Japan. Her big worry now, she says, are copycat designers who may start tampering with her zillion-dollar idea. "It's meant to be a simple thing," she says earnestly. "It's like a Zen rock garden. I want to keep the lawn chairs out."

—By Harriet Shapiro, with Kent Demaret in Houston