The square module (90 degrees)
Making the Modules --
Making the Polyhedra --
Jim's Origami Page
Start with a 4x3 piece of paper, and fold like an accordian into
Fold the lower left and upper right corners in. Use only the top layers.
Valley fold along the dotted line:
Fold the entire piece as indicated
Unfold back to a rectangle.
Remove the excess paper above and to the right of the thick lines.
Note that these lines do not fall on any crease lines.
This can be done with inside folds or with a pair of scissors
if you're willing to do so.
The final piece: