Freeware Descriptions:
A generic version of Tetris where you can adjust the geometry of shapes. Try monstrous 8-tile shapes, stuff shapes into a 3-cell wide well, or play a pure sixtis - tetris with only 6-block shapes.
Here is complete features (taken from authors site):

File Size / OS:
- 138.9 KB / Windows 9x - ME - 2000 - NT - XP - 2003 - Vista
Download Sixtis 1.4: