Atmosphere focused on explorable "worlds" (later officially called "environments"), which were linked together by "portals", analogous to the World Wide Web's hyperlinks. These portals were represented as spinning squares of red, green, and blue that revolved around each other and floated above the ground. Portals were indicative of the Atmosphere team's desire to mirror the functionality of Web pages. Although the world itself was described in the codice_1 (or codice_2) file, images and sounds were kept separately, usually in the GIF, WAV or MP3 format. Objects in worlds were scriptable using a specialized dialect of JavaScript, allowing a more immersive environment, and worlds could be generated dynamically using PHP. Using JavaScript, a world author could link an object to a Web page, so that a user could, for example, launch a Web page by clicking on a billboard advertisement (Ctrl+Shift+Click in earlier versions). By version 1.0, Atmosphere also boasted support for using Macromedia Flash animations and Windows Media Video as textures.