The Macintosh's GUI has been revised multiple times since 1984, with major updates including System 7 and Mac OS 8. It underwent its largest revision to date with the introduction of the "Aqua" interface in 2001's Mac OS X. It was a new operating system built primarily on technology from NeXTStep with UI elements of the original Mac OS grafted on. macOS uses a technology known as Quartz, for graphics rendering and drawing on-screen. Some interface features of macOS are inherited from NeXTStep (such as the Dock, the automatic wait cursor, or double-buffered windows giving a solid appearance and flicker-free window redraws), while others are inherited from the old Mac OS operating system (the single system-wide menu-bar). Mac OS X 10.3 introduced features to improve usability including Exposé, which is designed to make finding open windows easier.