Blog Post Image: Mathematical framework: How a wrinkle becomes a crease

The natural history of wrinkles, creases, and folds. With increased compression, a flat surface with a stiffness boundary layer (a) can become a wrinkle (b) and then a fold (c). Other possibilities include an instantaneous crease (d), a wrinkle-crease (e) or a fold-crease (f). Image credit: Brown University