In mathematics, a fibrifold is (roughly) a fiber space whose fibers and base spaces are orbifolds . A wallpaper group (or plane symmetry group or plane crystallographic group ) is a mathematical classification of a two-dimensional repetitive pattern, based on the symmetries in the pattern. In mathematics, a distributive lattice is a lattice in which the operations of join and meet distribute over each other. A fibroblast is a type of biological cell that synthesizes the extracellular matrix and collagen, produces the structural framework (stroma) for animal tissues, and plays a critical role in wound healing. Fibroblasts are the most common cells of connective tissue in animals. Reticular fibers , reticular fibres or reticulin is a type of fiber in connective tissue composed of type III collagen secreted by reticular cells. Reticular fibers crosslink to form a fine meshwork (reticulin). This network acts as a supporting mesh in soft tissues such as liver, bone marrow,