 In the 1970s, Engelbart's ideas were further refined and extended to graphics by researchers at Xerox PARC and specifically Alan Kay, who went beyond text-based hyperlinks and used a GUI as the main interface for the Smalltalk programming language, which ran on the Xerox Alto computer, released in 1973.Most modern general-purpose GUIs are derived from this system.The Xerox PARC user interface consisted of graphical elements such as windows, menus, radio buttons, and check boxes.