This design is composed of a series of waterbomb bases, one of the most widely recognizable folds in origami. The canvas, however, does not begin with a square, but a piece of paper with a 2:1 ratio. As far as the material and weight of the paper go, it all depends on the folder’s preference. A lighter paper won’t retain memory as well and a heavier paper might offer too much rigidity, making the paper very difficult to fold. These repeating waterbomb bases allows the overall form of the structure to curl around in to a sphere shape and also morph in to a cylindrical shape when equal pressure is applied to the sides. When equal pressure is applied to the top and bottom, the structure begins to collapse on itself, creating a donut shape.
Below is a diagram of the folding pattern. The red line indicates a valley fold, the blue line indicates a mountain fold, and the black line indicates a cut line. Although it’s extremely difficult to see in the diagram, each red X square is 1 waterbomb base. Every even row is offset by every odd row by half of a waterbomb base. For instance, if the canvas size is 20 inches by 10 inches, then the top row has 20 waterbomb bases adjacent to each other. This makes every water bomb base in the pattern 1 inch by 1 inch. The second row is shifted horizontally by 0.5 inches. This cascading pattern repeats itself. While folding this structure, it’s best to start in 1 corner and work your way diagonally to the opposite corner since each waterbomb base affects its immediate neighbor.