Squeak and its successor Newsqueak are concurrent programming languages for writing application software with interactive graphical user interfaces. Squeak was designed by Luca Cardelli and Rob Pike at Bell Labs in the first half of the 1980s; Newsqueak was a further development by Pike. Both languages were presented as "a language for communicating with mice": their main aim was to model the concurrent nature of programs interacting with multiple input devices, viz., keyboards and mice.