Clever designers have come up with a temporary building that will do the job of trees. Trees keep the air clean, provide shade and act as meeting and gathering points in open spaces. These ingenious contraptions apparently do the same. Made of steel, thermo textile and solar panels, the interesting-looking rotundas even create all the energy they need to light themselves. So, next time you forget to include trees in your plans, stick some of these in their place while the trees grow.