Granny knot its possible use tying the necks of grain sacks. When attempting to tie a reef knot (square knot), it is easy to produce a granny knot accidentally. This is dangerous because the granny knot can slip when heavily loaded. A tightened granny knot can also jam and is often more difficult to untie than the reef knot. It is better to tie a reef knot in nearly all circumstances. One way to distinguish them is that in the reef knot each loop passes completely over, or completely under (not through) the neck of the other. The reef knot is commonly
The purpose of a system is what it does or sheer ignorance of circumstances." The term is widely used by systems theorists. It is generally invoked to counter the notion that the purpose of a system can be read from the intentions of those who design, operate, or promote it. From a cybernetic perspective complex systems are not controllable by simple notions of management, and interventions in a system can best be understood by looking at how they affect observed system behavior. When "side effects" or "unintended consequences" reveal that system behavior is poorly understood, then taking the POSIWID perspective allows the more political understandings of system behavior to