In one corner of the schoolroom, Eman Said kneels over a pile of yellow plastic bags. She gathers three bags and begins to braid them into a plump rope.

For her school project, Eman has to think about new ways to use old materials. She'll design a home that will be built, at least in part, from recycled goods. Braided plastic could be used for a rug, she figures. Or maybe a blanket.

Across the room, Eduardo Chavelas waves some newspaper. The paper has been rolled and torn at one end, and, as he shakes it, the fringes blow in the breeze. "These are trees," Eduardo explains.

For his school project, Eduardo has to understand shade and sun and wind. For many minutes, he sits cross-legged and waves the trees. He seems to be pondering how a home could be cooled using a minimal amount of electricity.

It is a Tuesday in April. Earth Day, in fact. A group of Salt Lake architects stand before the sixth-graders of Rose Park Elementary.

The students sprawl on the floor, surrounded by old cardboard boxes and newspapers and scraps of fabric, metal and plastic. The architects, employees of the firm of GSBS, are the ones who gave them the assignment to choose an environment and design a house to fit the environment.

During the past week, the students have drawn pictures of the homes they want to build. This morning they are making a model. The architects asked them to be able to answer several questions about the home.

"Where will it be built?" the architects asked. "Who is it for and what will they need?" And finally, "How can you make your new building sustainable?" The architects have already explained to the students that "sustainable" means "something that keeps our environment at least as good as it is right now."

Today, the students explain their concepts to the grown-ups. The architects hear about a hotel in the forest. They hear about a home on an island and about another in a forest. In all cases, the needs of the occupants will include a television set.

One group of three boys and two girls is building a house in the mountains, and the architects learn that the intended occupants are the three boys who are building it. "Well, what about the girls?" the reporter asks, wondering if they'd prefer to be building a house they could live in. "They are our aides," one boy explains.

The girls, Andrea Batalla and Stephany Blanco, do not pause in their work. They shrug off the boys' description of themselves as the bosses as they calmly continue to measure cardboard.