It has become commonplace in histories of computing to separate the uses of computers as calculating engines and thinking machines from their more widespread applications for communication, knowledge work, creativity, and information sharing. An eclectic group of computer-science pioneers working in the 1960s, including J. C. R. Licklider, Douglas Engelbart, Ted Nelson, Ivan Sutherland, and Alan Kay, has received credit for shifting the emphasis from computational power to human use. A persistent aspect of the use of computers since the 1970s— alongside efforts to increase, augment, and extend human productivity—has been entertainment, and more specifically, play.