Cuis is a SqueakSmalltalk fork, with a focus on reducing system complexity.
Some highlights by the main developer, taken from his web site:
''Some of the main ideas and objectives for Cuis are:
- Close to the ideas in Smalltalk-80 and "Design Principles Behind Smalltalk".
- Includes only kernel functionality + dev tools.
- Included code should be of high quality.
- Includes a greatly simplified and enhaned Morphic as the main UI.
- Easy to fix and extend.
- Reasonably stable. Smalltalk kernel should not change much.''