Architecture is not a simple concept; it consists of a diverse set of many elements.  Architecture has a system of orders, or regulations for each of its categories, that being space, structure, and materials.  A building itself has 3 significant systems; structural, enclosure, and mechanical. The structural system allows the building to support and stand itself. The Enclosure system withstands any dangerous force from entering the building. It is the envelope of the building-regulating both the outside and inside. The last system is known as the mechanical system which, provides crucial utility to a building,  such as managing the heating, electrical system, sewage, and water system. In order to bring all these building systems together, we rely on certain materials to help with maintenance as well to serve different purposes. Materials include wood, concrete, steel, and masonry. A material such as steel has different types of durability and strength. For example: stresses at the top beam resist compression, whereas at the bottom tension occurs. When talking about character, however, big sections of wood will last longer in heat, than steel, but steel can be protected by fireproofing built brick around it. Therefore different materials distribute different purposes.