a shape having one or more sharp angles

make ridges into by pinching together

any of various types of fold formed by doubling fabric back upon itself and then pressing or stitching into shape

a sharp bend in a line produced when a line having a loop is pulled tight

an irregular fold in an otherwise even surface (as in cloth)

a continuous parallel folding in an accordion-like fashion, that is with folds alternatively made to the front and back in zig-zag folds.