 This work helped launch the field of computer animation.He also developed Smalltalk, a novel computer animation system for children, at the Xerox Palo Alto Research Center in 1974 and worked on interactive computer graphics and guided the realization and testing of the animated icon from 1988 through 1990.Continuing on his work on software visualization, between 1973 and 1981, he produced the film Sorting Out Sorting – a seminal piece elucidating the potential of computer animation and behavior that propelled the field of algorithm animation.