In the 1960s and early '70s, you couldn't say you had contemporary interior design if you didn't have a rya rug. These brilliantly colored rugs, which were like shaggy abstract paintings, aren't to be walked on.

Set against the prevailing teak furniture and sliding glass walls of the period, they brought color and texture to warm up simple furnishings. Because of mass production and mass marketing through stores such as Scan here in Washington, even young families were able to buy at least one rya.

Now thanks to a small but intriguing show at the Renwick Gallery through March 16, we can see how the rya came to Finland and what the talented Finns have done with it. The show is accompanied by a small catalogue, which provides an interesting history of the rya and some photographs so fuzzy they look shaggy. Fortunately you can see the rugs for yourself at the Renwick before they begin a country-wide tour organized by the Smithsonian Institution Traveling Exhibition Service.

The Finnish word is "ryijy." The Swedish "rya" is more familiar. Both apparently derived from the ancient Scandanavian word "ry" or "ru," meaning rough and shaggy. Rita Pylakkmene of the National Finnish Museum, writing in the catalogue, says that a type of rya is found in 9th century excavations in southern Scandanavia.

The ryas were shaggy like the furs they replaced. pylakkmene suggests they came to Finland from Scandanavia as a sleeping rug used on boats. By the mid-15th century they were being woven in a Finnish convent. They soon became popular as bed covers. Some versions were double piled, shaggy on both sides. They were sometimes used as payments for taxes.

Regrettably, and understandably, the Finns were loathe to send us any of their really old ryijys; but two date back to 1799, incorporating the year of their design. One rug has all stick figures surrounded by a tree of life design. The other is more free form and incorporates the initials of its maker. Both are reminiscent of the sort of paintings that you see on chests and cupboards of the period. Five more are from the 1800s.

The functionalist 1930 design by Impi Sotavalatla is especially good. It is a pity that there are none in the art nouveau and art moderne styles designed by Eliel Saarinen and his wife, who established a craftsman's guild in Finland before coming to America to open Cranbrook Academy of Arts in Detroit.

In the Milan Triennial of 1951, the place of Finland at the head of contemporary design was established, not the least in the exhibition of ryiji tapestry. This work has influenced all of modern tapestry design, especially that in the United States. From that period is a rug in the show by Uhra Simberg-Ehrstrom. Not quite half the show is made up of 1970s rugs, which seem very familiar. Now it seems that we could use a much larger show with historical ryas from several Scandanavian countries.