Imagine a lake that is small in one season and much larger in another. In Cambodia, the Tonlé Sap lake can grow by up to five times when the Mekong River overflows in rainy weather, UNESCO explains. Where would you put a home beside water that changes this much?

The Food and Agriculture Organization describes floating villages on the lake’s water. A floating village rests on the water instead of on dry ground. That is one answer to a puzzle many riverside and lakeside places share. Your first drawing may have used a different answer, such as a raised floor. Compare them without deciding that every home beside the lake must look alike.

Neither description promises safety, and neither gives us building plans. A feature can help with one problem and still have limits. Ask what a home is responding to, rather than judging it by an unfamiliar shape.

Put your roof idea beside your raised-floor drawing. Both involve water, but they tackle different puzzles. Your roof trial follows water arriving from above. Some Mising homes in Assam, India, have floors raised on bamboo stilts, one response to floodwater rising below, according to a United Nations account. Could a house need to deal with both?

Now travel in your reading to Shirakawa-go and Gokayama in Japan. Their gassho-style houses have steep roofs covered with thatch, a layer of plant material. UNESCO connects their design with the local environment and work such as raising silkworms. A house needs room for people and for what they do. Roof shape is only one part of that story.

In the Mising example, bamboo, timber, newer materials and changing costs also matter. Compare these two named examples with your home. Which feature would you ask about first? Try a paper design that combines your roof and floor ideas. Trace rain from above and rising water below. Your model gives you questions to investigate, rather than one best home for everyone.

together · About 10-15 minutes; untested estimate.

You need

• Waxed paper or foil
• Four plastic cups
• Tray and paper towel
• Water and spoon
• Pencil

Try it

1. Make equal flat and peaked roofs from the same material.
2. Rest each roof across two cups in a tray.
3. Put a small dry paper towel below each roof.
4. Spoon the same small amount of water onto each roof.
5. Notice where water goes and whether either towel gets wet.
6. Draw one revised roof or raised-floor idea.