the pagoda (from Maying Soong) and the lotus made from Joss paper. Most traditional designs are however single-piece and the possibilities inherent in the modular origami idea were not explored further until the 1960s when the technique was re-invented by Robert Neale in the US and later by Mitsunobu Sonobe in Japan. The 1970s saw a sudden period of interest and development in modular origami as its own distinct field, leading to its present status in origami folding. One notable figure is Steve Krimball, who discovered the potential in Sonobe's cube unit and demonstrated that it could be used to make alternative polyhedral shapes, including a 30-piece ball. Since then, the modular origami technique has been popularized and developed extensively, and now there have been thousands of designs developed in this repertoire. Notable modular paperfolders include Robert Neale, Sonobe, Tomoko Fuse, Kunihiko Kasahara, Tom Hull, Heinz Strobl and Ekaterina Lukasheva. Types Modular origami forms may be flat or three-dimensional. Flat forms are usually polygons (sometimes known as coasters), stars, rotors, and rings. Three-dimensional forms tend to be regular polyhedra or tessellations of simple polyhedra. Modular origami techniques can be used to create lidded boxes which are not only beautiful but also useful as containers for gifts. Many examples of such boxes are shown in Fabulous Origami Boxes by Tomoko Fuse. There are some modular origami that are approximations of fractals, such as Menger's sponge. Macro-modular origami is a form of modular origami in which finished assemblies are themselves used as the building blocks to create larger integrated structures. Such structures are described in Tomoko Fuse's book Unit Origami-Multidimensional Transformations (published in 1990). Modeling systems Robert Neale's penultimate module Neale developed a system to model equilateral polyhedra based on a module with variable vertex angles. Each module has two pockets and two tabs, on opposite sides. The angle of each tab can be changed independently of the other tab. Each pocket can receive tabs of any angle. The most common angles form polygonal faces: 60 degrees (triangle) 90 degrees (square) 108 degrees (pentagon) 120 degrees (hexagon) Each module joins others at the vertices of a polyhedron to form a polygonal face. The tabs form angles on opposite sides of an edge. For example, a subassembly of three triangle corners forms a triangle, the most stable configuration. As the internal angle increases for squares, pentagons and so forth, the stability decreases. Many