To create even more complex models, the modular origami has evolved to one which is to fold a very simple basic unit (most of the time is just a triangular pocketed wedge) in count of thousands, then carefully interlock them together to form the object. The paper used are mostly stiffer paper for holding up the structure. To practice this type of origami, one need to have basic folding skills and moderate assembly skills. For this type of origami, they need not follow the rule of folding the units with square paper. This type of origami focus on folding simple units, more like the extended LEGO bricks set, and then carefully assembled them into the target object, which are mostly resemble the molecular or lattice structure found in Mathematics or Chemistry textbook. When the complex models has reached new heights, there is another school of origami growing in strength - they are the Modular Origami. To practice Complex Origami, one need to have good folding skills and special paper. Yet all are done with the same uncut perfect square paper.
It ranged from simple models where young children are being amused by their imagination on the premitive but yet symbolic folded features to capture the spirit of the folded object, to the most complex models where fine details are being folded to the level not less intricate than the chiselled sculpture. This alone has already created thousands of models. A piece of uncut perfect square to be exact. The true traditional art is to fold with not just any shape of paper, but only from a perfect square. Unlike common understanding who treat origami as just folding paper into objects.