I learned how to make this modular origami cube from the book
Marvelous Modular Origami by Meenakshi Mukerji.

One of the simplest models presented in the book is a small cube,
which consists of six units folded identically, then interlocked using no glue or tape.
The book contained a few different patterns for folding the units.
The one used in this cube is called "Snow-Capped I".  It's my favorite.

Origami folding patterns are usually presented in diagrams with standard folding symbols.
After folding a few origami patterns,
the symbols and the various folds become quite familiar.
The diagrams in the book were copyrighted, so I could not include them here.

Each face of the cube is made up of the center square of one unit
and the tabs of two other units.
The tabs fit into flaps created by the folds in the unit.
The first few pieces need a bit of coaxing to stay together.

There now, don't you want to try one of your own?