LIKE A GOOD PATCHWOOK 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 meals 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 desert, 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 soupy 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, 11:30 a.m. to 11 p.m. No credit cards. Reservations.

Chevy Chase holds its breath every time the Thai Room makes a change The dining room was redecorated. A liquor license was gained. The next-door grocery was abbreviated to add more dining space. The menu was expanded.And finally, as faithful patrons grew faint with fearful expectation, it came - a price increase. Noodle and rice dishes were up, and some of the pork dishes were too. By a monumental twenty-five to thirty cents. The upshot? The Thai Room is still the lowest-priced Thai restaurant in town, with main dishes averaging $3.

There is a certain leeway one must give a bargain restaurant. Though the Thai Room is now walled in blue flocked wallpaper, and has candles on the tables and chandeliers hanging from the ceiling, it uses no tablecloths, and the tables are still packed into a rather small space. But it is pretty in a simple way, clean, and friendly. Also, in a bargain restaurant one shouldn't be surprised to find some of the portions small of skimpy on meat, particularly when rice is meant to be the staple of the meal.

But the Thai Room is more than a bargain. At any price, consider the following: Thai Room special chicken, five pieces of chicken molded around a bone, fried in a crisp batter, stuffed with shredded crab, scallions and dried black mushrooms, alongside a dipping sauce of sugar and spice, hot peppers being the spice. Satay, a dozen small skewers of bits of beef or pork, lightly seasoned with fish sauce and grilled lightly, just enough to cook through and absorb a charcoal flavor, accompanied by a sweet, faintly peppery chopped peanut sauce. Tod mun, or spicy fish cakes, are chewy fried fish croquettes dotted with hot peppers, yet they are neither very fishy nor very peppery, merely succulent.

If your tongue likes an occasional singeing, try lab, a cold dish of chopped meat seasoned with lemon and nam pla and more pepper than you can believe, with lettuce to roll it into a crisp sort of sandwich. Or maybe ask them to go easy on the pepper. But those are just appetizers, merely the beginning.

Soups here are an experience, and experience in piquancy, in the case of tart, perfumy shrimp and lemon grass soup or salted mustard green soup which tastes something like liquied sauerkraut with pork. But if you are fond of coconut an dhot peppers, experience the chicken an d galanga and coconut milk soup.

Attacking the main dishes, there are seven noodle dishes, perhaps the most interesting being the sweet-sour Thai-style noodle with bean sprouts, scallions, coriander, shrimps, meat, peanuts and egg. Beef, pork, chicken and shrimp can be ordered with hot chili, with basil, with ginger, with various vegetables or with pepper or chili and garlic, which is the kind of dish that drives tears to your eyes because it is so hot, but you can hardly resist another bite. Sauces are free of oil and starch, just thin, lively seasonings. Vegetables border on the raw, and taste very fresh. Fish range from tiny crisply fried ones smaller than smelts to whole large fish either fried or steamed; there is even catfish. Among the menu's "other specialties" are a delicately flavored steamed omelet called Thai-style scrambled eggs, and a daily curry, in our case a combination of chicken and eggplant in a green-gold coconut-flavoured broth scented with basil.

And if you like what you ate, you can buy the ingredients to try it yourself at the adjacent grocery store.