In the 1990s, in The Ecology of Commerce, Paul Hawken translated these ideas into three basic rules for sustainability : waste equals food; nature runs off current solar income; and nature depends on diversity. He also proposed replacing our product-sales economy with a service-lease model, famously using the example of Interface ‘Evergreen’ carpets that are leased and constantly replaced and recycled. William McDonough and Michael Braungart have extended this thinking in their Cradle to Cradle industrial model. Cradle to cradle is not only about closing the loop on production, but about designing for ‘good’, rather than the CRS 1.0 modus operandi of ‘less bad’.