Block (sailing) Block (sailing) In sailing, a block is a single or multiple pulley. One or a number of "sheaves" are enclosed in an assembly between "cheeks" or "chocks". In use, a block is fixed to the end of a line, to a spar, or to a surface. A line (rope) is "reeved" through the sheaves, and maybe through one or more matching blocks at some far end, to make up a tackle. The "purchase" of a tackle refers to its mechanical advantage. In general the more sheaves in the blocks that make up a tackle, the higher its mechanical advantage. The
The purpose of a system is what it does The purpose of a system is what it does The purpose of a system is what it does (POSIWID) is a systems thinking heuristic coined by Stafford Beer. Stafford Beer coined the term POSIWID and used it many times in public addresses. In his address to the University of Valladolid, Spain, in October 2001, he said "According to the cybernetician, the purpose of a system is what it does. This is a basic dictum. It stands for bald fact, which makes a better starting point in seeking understanding than the familiar attributions of good intention, prejudices about expectations, moral judgment,