Hi
If you search the internet for “box pleat” the first results you’ll get are from sewing and not origami. According to Wikipedia, in sewing, a box pleat is defined as: Box pleats are knife pleats back-to-back, and have a tendency to spring out from the waistline. They have the same 3:1 ratio as knife pleats, and may also be stacked to form "stacked-" or "double-box pleats". These stacked box pleats create more fullness and have a 5:1 ratio. They also create a bulkier seam. Inverted box pleats have the "box" on the inside rather than the outside. And to understand that, you need to know that a knife or accordion pleat is: Accordion pleats or knife pleats are a form of tight pleating which allows the garment to expand its shape when moving. Accordion pleating is also used for some dress sleeves, such as pleating the end of the elbow, with the fullness of the pleat gathered closely at the cuff. This form of pleating inspired the "skirt dancing" of Loie Fuller. Accordion pleats may also be used in hand fans. I don’t know much (actually I don’t know anything at all) about sewing but what is said here about these pleats seems similar to what could be said of the ones used in origami. So could it be that origami borrowed the term “box pleat” from sewing? -- Jorge Jaramillo
