Squeak is the name of a free open source implementation of Smalltalk. It is available on many platforms and the programs produced on one platform run bit-identical on the other platforms. The Squeak system includes code for generating a new version of the virtual machine it runs on. It also includes a virtual machine simulator in itself. For this reason it is easily ported.
It comes with a graphic framework called Morphic modeled after the one of Self. The framework allows direct manipulation of graphical objects. Morphic is an alternative to the traditional Model View Controller (MVC) interface of Smalltalk-80, which is also present in Squeak.
Squeak incorporates many of the elements Alan Kay proposed in the Dynabook concept, which he formulated in the 1960s. Kay is an important contributor to the Squeak project.