Here are other applications of the mountain fold symbol.
Although we suggested on page 14 that a mountain fold can be made by forming a valley fold and then turning it upside down, this is not always possible, as the example below shows.
In this example, it is useless to turn the sheet upside down. You would have to unfold the upper layer, make a valley fold, and then return to the previous position in order to reach the desired orientation.
The Hidden Edge Line
A fine dotted line is used to indicate the location of an edge that is not visible. When necessary, the hidden edge, as in fig. 1, is represented as in fig. 2.
In general, all hidden objects are drawn with a dotted line starting at the point at which they disappear from view. The same applies to arrows.
Fig. 1 requires that the white sheet be tucked beneath the colored layer. The arrow indicates the order to be followed. At the point where the arrow passes beneath the colored layer and thus becomes hidden from view, its line becomes dotted. In fig. 2 one can easily deduce that the dotted line represents that part of the white sheet that has been inserted beneath the colored layer.
The Repetition Symbols
The “repeat arrow” is another symbol that you will come across in the model at the end of this chapter. For example, in order to fold four corners towards the center of a square, the same move must be completed four times. Usually the first fold is indicated by a complete arrow. A short, straight arrow with three perpendicular marks on the shaft indicates that the same fold must be repeated three more times.
If a fold needs to be made on only two corners of a square, the first fold can be indicated by a complete arrow and the second by a short arrow with one perpendicular mark. The number of marks indicates the number of times the fold must be repeated. Thus, for example, if the corners of an octagon need to be folded towards the center, the first arrow may be depicted along with another arrow with seven perpendicular marks. The repeat arrow may also be applied to an edge.
Repetition can also be applied to an entire sequence of steps already completed. In such cases, an arrow with a single perpendicular mark is paired with the numbers of the steps to be repeated.
The meaning of the directions here is to repeat steps 4–7.
The Enlarged View Symbol
“Enlarged view” is another important origami symbol. It indicates that the figure which the arrow is pointing at is no longer to scale but is enlarged. It is used when the dimensions of the figure become too small for the instructions to be read properly. It can also be used to clarify certain details, such as the number of superimposed layers, or to highlight the instructions for carrying out a particular fold.
Enlargement may be applied to only a portion of an illustration. In such cases, the enlarged part is usually highlighted in a circle or oval, as in the figures below.
The Reduced Scale Symbol
Sometimes the opposite may occur. When an illustration becomes too large, a “reduced scale” arrow is used.
Recommended paper size: 6¾ x 9¼ inches (17 x 23.5 cm)—A4 format works as well
Crease pattern showing the finished model’s folds
The initial sheet of paper and the final model juxtaposed
Practice Model:
Rectangular Box
Make a valley fold, bringing the right over to the left edge, and then unfold.
Make two valley