Squeak
Squeak is the name of an 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. The graphical object are in a display tree hierarchy. It replaces the traditional Model View Controller (MVC) interface of Smalltalk-80.
