Three is:module

Tools for 3-way partitioning.
This module defines the three-dimensional vector space R^3, three-dimensional transformations, and various predefined three-dimensional shapes. This module re-exports useful functionality from a group of more specific modules:
A convenience module, combining all raw modules containing 3DFX extensions.
A layout similar to tall but with three columns. With 2560x1600 pixels this layout can be used for a huge main window and up to six reasonable sized slave windows.
A layout similar to tall but with three columns. With 2560x1600 pixels this layout can be used for a huge main window and up to six reasonable sized resizable stack windows.