ABSTRACT
The first of the two families of folds is the parallel folds. Parallel folds can result from cloth lying over a cylindrical shape, or from pressure that pushes the material evenly and bends it evenly. An important characteristic of parallel folds is that they stay the same size along their length. A parallel fold can come full circle and be sewn to itself to form a sleeve or pant leg. Applying even pressure sometimes causes several parallel folds to form as neighbors in a group. As they interlock with each other, they alternate between having their convex and their concave sides up, in a sequence of hills and valleys. Zigzag folds can be subtle with slight angles. Greater compression will make the zigzag fold's angles sharper, and the line segments shorter, if the sides of the material are constrained.
