Designer Koos van den Akker was asked to describe his patchwork sweater. "Well, it's got chiffon and lurex and leather and silk on it," he said. "It's not very practical I suppose. I don't know how to clean it."

Fantasy, not practicality, is Koss van den Akker's strong suit. And his customers clearly like it that way. Joan Kennedy stopped in his Madison Avenue shop recently and bought three hand-knit sweaters. Gloria Vanderbilt, Cher and Marlo Thomas are among his regular customers. Last year Elizabeth Taylor called to order a suit she had seen, but she wouldn't give her size. ("She's above that -- she shouldn't have to give her size.") Van den Akker's pattern maker studied all the recent magazine photos of Taylor and made up a suit. Apparently it fit; Van den Akker says he saw a picture of her in it sometime later.

Van den Akker, who will be lecturing at the Simthsonian tonight, doesn't concern himself much with anything in this business except sitting behind a sewing machine every day and making collages on fabrics. "Just give me a sewing machine and a pile of fabrics. That is my fun," he says. "It is like painting with a sewing machine."

He starts with no plan, no order, no boundaries. "I never know how they are going to turn out," he says. "Each season I start with clean lines. But it always comes out beserk. I can't help it."

His current collection is Venetian, inspired from a trip there with a friend last fall. "The light in Venice is different from anywhere else, the crumbling palazzos, the color of the water . . . it all affects what I have done," he says.He points to a leather applique on a tweed skirt. "It's like the floor of a Venetian palazzo."

The experience, he says, also made him decide to use a male friend in his fall opening to show off several of his women's designs. "I wanted to show Venetian decadence -- decadence in old Venetian style," explained Van den Akker at Bloomingdale's recently. "I could have put the models in masks and hats. But this had the sharp edge I always like." Besides, he added later, "using just models is so boring. I wish I could train animals."

The Dutch-born designer, who worked as an unpaid apprenctice making buttonholes, collars and all the details at Christian Dior in Paris for three years, came to New York in 1968. He says he perched himself by the fountain at Lincoln Center and peddled his clothes by saying to strangers, "I'm from Holland. I need some women to dress. Would you let me make you a dress . . . or one for a friend?" Back then his dresses cost $23 to $30. Today his price tags run at least 10 times that.

From the start -- even at age 4 when he was making dresses in crepe paper -- his clothes had patchwork. "I seldom have any plain fabric. I can't resist patching it up," he says. "It makes my clothes exclusive and different."

Each design is individually done and likely to be different from the next. And when more than one of the same design is made -- though never more than about 50 for the entire country -- he selects 20 or so fabrics that work together.An artist then cuts them up and place them in the collage.It makes everything pretty much one of a kind.

"I have a gift for colors and combinations," he says. "I have a lot of it, and now I even have an audience for it."

His customers are partial to his daytime clothes -- some with minimal contrast used almost like banding on a jacket, others with an elaborate design such as one that starts at the front of a coat and continues to the back. "I don't do baroque things . . . Oscar [de la Renta] does that. And simple things Julio does. But the sportswear that everyone does is dull as hell. I can give it something special," he says. "Either you like it, or you don't. That makes it simple."

Apparently a lot of people like it. In the last year, his wholesale business has grown from $285,000 to $1 million.