Squeak 3.7b-5

Squeak is a full-featured implementation of the Smalltalk programming language and environment based on (and largely compatible with) the original Smalltalk-80 system.
Squeak has very powerful 2- and 3-D graphics, sound, video, MIDI, animation and other multimedia capabilities -- and one of the most impressive development environments ever created.
It also includes a customisable framework for creating dynamic HTTP servers and interactively extensible Web sites. The entire Squeak system is open source software, distributed freely with a liberal license.
Main features:
- real-time sound and music synthesis written entirely in Smalltalk
- extensions of BitBlt to handle color of any depth and anti-aliased image rotation and scaling
- network access support that allows simple construction of servers and other useful facilities
- it runs bit-identical on many platforms (Windows, Mac, Unix, and others)
- a compact object format that typically requires only a single word of overhead per object
- a simple yet efficient incremental garbage collector for 32-bit direct pointers
- efficient bulk-mutation of objects