He was standing, tall and intense, on a small slope, his lips tight in concentration, urging first his right leg and then his left into a snowplough-turn position.

Immersed in the reality of a snowy day at the ski resort, Gregory Dill, 19, was far from the fantasy world of cartoon characters and make-believe that once occupied many of his waking hours.

When he was 8, Dill didn't talk. At 15, he responded to questions in short phrases but he would not start a conversation. Diagnosed as mildly autistic, he felt frustrated and isolated. He often abandoned the difficult struggle to communicate with those around him.

Now the Silver Spring special-education student is a hero, winner of three cross-country skiing medals in state games and a chance to go for the Big Gold at the International Winter Special Olympic Games next month.

His trip to the international event -- at Smuggler's Notch in Stowe, Vt., March 8 through 13 -- will climax a winter of practice sessions at Ski Liberty and twice-weekly exercise classes at Mark Twain School in Rockville, conducted by Montgomery County Public School's Coordinator for Special Olympics Ralph Crawson.

Joining Dill at the international games next month will be two other special-education students chosen from among the 3,000 Special Olympics participants in Montgomery and Prince George's counties: Anthony Nedab, 17, a skater from Rockville, and Pam Horton, 17, a downhill skiier from Beltsville.

All three were winners of the state level competition, held at Wisp in western Maryland and including competitors from West Virginia and the District of Columbia. Nedab took a gold medal in speed skating; Horton won a silver in the downhill slalom and Dill won a gold in the one-dilometer cross-country and both a silver and a bronze in the 100-meter cross-country race.

At the big games in Stowe, the local trio and six other Maryland contenders will join more than 700 mentally retarded athletes from the United States and 16 other countries in a star-studded spectacular featuring a torchlight parade, demonstrations, prizes, dances and variety shows.

The games were established nationally in 1968 by Joseph P. Kennedy Jr. Foundation to create sports training and competition opportunities for retarded adults and children. Games were started in Maryland in 1970 by The Maryland Special Olympics Inc., a private, nonprofit organization.

The state program has grown from a single event (tract and field) offered 250 athlets to a 14-sport program covered by six separate torunaments and serving nearly 10,000 youngsters.

Sponsors of al phases of the program say the competitions do much more than improve athletic skills.

"They build confidence in each person, showing the indivdual that he can do things. This in turn builds self-esteem that shows up in the classroom, the job and the home, as well as the playing field," says Montgomery County's Ralph Crawson.

A prime example was the experience of Paul Bowers, an autistic and legally blind 14-year-old who attended the recent practice at Ski Liberty in Pennsylvania. Bowers, who attends the Maryland School for the Blind in Baltimore, skied for the first time that day with teacher Julie Gaynor skiing backwards in front of him, in constant hand voice contact. Bowers' reaction: a big grin and a loud, "I can ski!" made it obvious that the experiment was a success.

"Winning is just as important to these students as it is to everyone else," says Phyllis Horton, Pam's mother and leader of a family of avid skiiers.

"But Pammy (who is moderately retarded and attends the Duckworth School in Beltsville) has gotten a lot more than medals and attention out of sports. It's given her a special activity of her own. She knows she is different from her four sisters and she is proud to have her own schedule of events and her own friends to keep herself occupied and happy."

Dill, a student at the Bridge School at Einstein School in Kensington, participates in track and field, bowling, swimming and poly-hocky as well as skiing. Sports has been a major factor in his struggle to improve his "social interaction."

"Before he got into sports," says his mother Delores, "he didn't relate well to others. Since he's traveled around with Crawson's group, he has become more interested in team sports rather than just the solo activities like track."

After Dill won his medals in the state games earlier this month, he raised both arms in the familiar victory signal. Later, at the victory celebration, he, "danced with some ladies," had "some fun" and came home "running towards me beaming, the medals stuck out in front of him," said his mother.

Ed Bryan, principal at the Concord School in Bethesda, where Anthony Nedab is a student, said sports "has really opened doors" for Nedab by offering him "exposure to the attitudes and demands of the real world. . . ."

Another advantage, said Bryan, is that". . . the community (is) more aware of, less worried about, our kids and their needs. It had helped them understand mental retardation."

"When you see a group of kids in T-shirts and shorts on a regular high school field, you can't tell the special students from everyone else," added Bob Janus, Prince George's County Special Olympics coordinator. "That's in part because all these contacts with the other kids have given them role models. They've learned how to act normal."

The benefits of the Special Olympics programs are not limited to the few state and international contenders, however.

Coordinators such as Crawson in Montgomery County and Janus in Prince George's -- both are paid by their school systems and work as volunteers in the state Special Olympics program -- have seen to it that each special school's adaptive physical-education classes offer Special Olympics-style training. In addition, both provide afterschool and weekend training clinics and competition in a variety of sports, as well as trips to sports events.

Money and manpower for the program i n Montgomery and Price George's counties, as in the rest of the state, come chiefly from contributions and volunteers. Crawson estimates Montgomery's budget as "around $30,000, representing a $15,000 cash outlay" raised from contributions, a donation-in-kind valued at about $12,000 for the ice skating program (rinks, salaries and rental fees) provided by the Maryland-National Capital Park and Planning Commission and school board in-kind contributions (lights, use of vans and facilities, heating and janitorial services) values at about $3,000.

Janus said the Prince George's program costs about $21 per child, or a about $21,000 for the 1,000 children served. Funds are raised from private sources and supported in a addition by in-kind contributions from the school system.

For all the program accomplishes for the children, Prince George's Bob Janus says he isn't sure "who is being helped more: the kids or their parents. Special Olympics has gone a long way to unite families that have been devastated or maybe even disintegrated because of the pressures of raising a handicapped child.

"With this program, they walk away proud."