As they scurry from the playground, the four to six-year-olds press their noses to a window and blow kisses to their friends next door: the elderly people who share their building with a pre-school.
What started out as a marriage of convenience between facilities for the elderly and crowded child-care centres and pre-schools has given birth to a new discipline, inter-generational education.
"You can't help but get acquainted," said Rose Uchill, 84, a widow who has a bouquet of autumn leaves for a little girl she has befriended. "But we have to be careful not to smother them."
Two demographic trends have hastened this phenomenon: the number of Americans aged over 65 is projected to increase from 25 million in 1980 to 35m by 2000, according to the US Census. And kindergarten enrolment has grown from 30m to more than 37m in the past five years.
"It's something that organisations are looking at more as space becomes an issue, but mostly because the benefits to each side go beyond the economics, " said Judith Kline-Leavitt, director of a coalition of 120 such groups called Generations United.
Rose Uchill lives in Boston in an assisted-living centre, whose 90 residents have their own apartments but receive help with cooking, cleaning and medical care. Called Heritage at Cleveland Circle, it has a combination pre-school and day-care centre for about 100 children.
"This is a model that we should have many more of in our communities," said First Lady Hillary Clinton, who visited the building when it opened in the spring. "It is important not to isolate children and seniors, but to bring them together under one roof."
The pre-school and the residential section share recreation and music rooms, where the children and the elderly talk, sing, and do craftwork. One parent, Alex Sherman, said: "The parents can't be in the classroom all the time; the older people can. And here they don't feel that they're on the outskirts of life."
"Everybody's so spread out today," said Louise Hyman, 72, a resident of Heritage at Cleveland Circle. "So we really become an extended family."
The Heritage Day Health Centre in Columbus, Ohio, mixes elderly and disabled people with the children of mothers recovering from substance abuse.
"Nobody else has the kind of time that an older adult does to just sit and applaud for these kids and give them unconditional approval," said Bonnie Walson, the director.
Many of the programmes are affiliated with ethnic or religious groups. The pre-school at Heritage at Cleveland Circle is run by a Jewish organisation. The children at the Heritage Day Health Centres in Ohio come through the Young Women's Christian Association. And two Asian groups have jointly organised an inter-generational programme in San Francisco.
Irene Chan, supervisor of Wu Yee Children's Services, said: "Asian children are more respectful of the elders. But in this generation, most of the children are not living with their grandparents and don't have the education from their own parents to teach them how to respect older people."
"At Wu Yee," said Chan, "the children learn how to take care of older people, how to be gentle with them. And the seniors really light up when they see them. They see the smiles from the children and they smile, too."