LIKE A GOOD PATCHWORK quilt, Thai cuisine intermingles patterns as distinct as Indian, Chinese and Malay into one delicious fabric. As in most of Asia, the background of the meal is rice, upon which a palette of meats, seafoods, vegetables and sauces are daubed so that each plate becomes as individual as the diner who composes it. And the range of the palette is wide: curries as hot as the tropical sun, mellowed by the sweet fragrance of coconut milk; the piquancy of fermented fish sauce called nam pla, a cousin to soy sauce; the sharp herbal tones of mint, coriander leaves, basil and lemon grass; fiery chilies muted by chopped peanuts; garlic and ginger battling for power.

Temperature contrast, alas, is virtually ignored in Thai cuisine; it is common for an entire meal, from soup through dessert, to be served lukewarm. The style of food appears familiarly Chinese - small pieces cooked quickly - except that sauces are unthickened, just a thin, highly flavored moistening or a souply liquid floating meat chunks.

While desserts in America's Thai restaurants are either custards notoriously oversweet and dense, or simple canned tropical fruits, at the opposite end of the meal, the soups and appetizers are the highlights, the places to concentrate one's appetite. In fact, soups are often served as main courses, and appetizers are apt to be in portions as large as entrees.

Exotic as Thai food may sound, the restaurants here - there are three now - offer some delicious, lightly seasoned dishes that can capture even the timid and turn them into addicts. Given the fact that none of these restaurants averages more than $3.50 for main dishes or $3 for appetizers, this is one of the safer addictions available. Here are Washington's three Thai restaurants, in order of my preference.

Open daily, 11 a.m. to 10:30 p.m. AE, BA, CB, DC, MC. Reservations.

Family-run ethnic restaurants carry certain characteristics across nationalities, and this small restaurant runs true to its genre. Plastic tablecloths and flowers, portraits of the king and queen, universal-green walls, and a calculus book on a back table for the waitress to study on her off moments. The menus were in red folders, the king used for term papers.

Those youthful waiters who are being educated for other professions were very good at this one, articulately explaining the menu and deftly handling several tables at a brisk place.

The appetizers numbers only four here. There are two kinds of satay so bad we wondered if they were meant to be eaten; delicious fish cakes (tord mun pla on the untranslated menu), peppery but not truly fiery, chewy yet succulent; and fried, subtly flavored crab puffs, fairly good.

Oh, the chicken with coconut soup! If you like perfumed dishes, you will long remember this one, creamy white and powerfully coconut-scented, faintly peppery and lemon-tart. The fragrance is intensified by big woody pieces of the sweetest ginger root this side of Bangkok, and large green leaves - both of which must be fished out rather than eaten.

But you must step carefully through the rest of the menu, for too many dishes are bland, tasteless, greasy, overcooked. Chicken with chilis, for instance, presented with a warning that it was very hot, would have been no threat even to a Cantonese palate. Two dishes to note are Thai House Special Salad, much like Indonesian gado gado, a mix of slivered pork, sliced hard-cooked eggs, lettuce, and other vegetables in a slightly spicy-sweet peanut sauce. And fried watercress, though greasy, was a wonderful salty crunch of vegetable. Dessert-like is the very sweet, unique Thai coffee. It is better than the tea, which is merely Lipton's tea bags.

Thai House is not a heavy in the Thai food field, but it is worth a chance if you are in the neighborhood.