In the course of office work, it is common for people to organize documents in terms of piles, such as an in-box, out-box, a pile of urgent items, and a pile of less urgent items From a perspective of sensemaking, piles are an external representation with several interesting properties At least in the physical world, documents can be in at most one pile at a time -- so that piles represent disjoint categories Piles have a complete ordering The top item of a pile is more visible than lower ones Sometimes the edges of items in a pile can be seen Items in a pile can be sorted according to some criterion Virtual piles can also be created as a user interface Virtual piles can be useful for putting documents or other things in disjoint categories (They can also be extended beyond the properties of physical piles so that an object can be in more than one pile at a time, or can have corresponding "ghost" objects to represent it in more than one pile )
A support made of wood, concrete or other material that is driven or embedded into the ground Examples include wood pilings used with elevated, coastal homes