In electrical engineering, a style may often begin as a rather significant level block diagram, getting more and more detailed block diagrams as the design develops, finally ending in block diagrams comprehensive enough that each individual block is readily implemented (at which stage the block structure will be also a schematic diagram). This is referred to as top down design.  Geometric shapes are often utilized at the diagram to aid interpretation and clarify meaning of this process or model. The geometric shapes are connected by lines to indicate association and direction/order of traversal. Each engineering field has their own meaning for every form. Block diagrams are used in every discipline of technology. They are also a valuable source of theory building and educationally beneficial in non-engineering areas.
To create an analogy to the map which makes world, a block diagram is very similar to a highway map of an entire nation. The significant towns (functions) are recorded but the small county roads and city roads aren't. After troubleshooting, this large level map is helpful in narrowing down and isolating where a problem or fault is.
A block diagram is a diagram of a method where the main components or works are represented by cubes joined by lines which reveal the connections of the cubes. They are greatly utilised in engineering in hardware design, digital design, software design, and process flow diagrams.
Block diagrams are typically used for higher level, less comprehensive descriptions which are intended to clarify general theories without difficulty for the details of implementation. Compare this with the schematic diagrams and layout diagrams used in electrical technology, which reveal the implementation information of electrical components and physical structure.
In process management, block diagrams are a visual language for describing activities within a complex system in which cubes are black boxes which represent logical or mathematical operations that exist in sequence from left to right and top to bottom, although not the physical things, such as processors or radiators, that execute these operations. It's possible to create such cube diagrams and execute their functionality with specialized programmable logic control (PLC) programming languages.
As an example, a block diagram of a radio is not expected to demonstrate each and every connection and dial up and change, however, the design diagram is. The schematic diagram of a radio doesn't show the diameter of every link in the printed circuit board, but the layout diagram will not.
An example of this is that the function block diagram, among five programming languages described in part 3 of the IEC 61131 (view IEC 61131-3) benchmark that is very formalized (see formal system), with stringent rules to how diagrams must be assembled. Directed lines are utilised to link input factors to block input signal, and prevent outputs to output variables and inputs of different blocks.
Block diagrams rely on the principle of the black box in which the contents are concealed from view either to avoid being distracted by the details because the details are not known. We know what happens, we all know what goes out, but we can't see the way the box does its work.
In biology there is a growing use of technology fundamentals, techniques of investigation and ways of diagramming. There is some correlation between the block structure and what is called Systems Biology Graphical Notation. Since it is there's use made in systems biology of the block diagram technique exploited by controller technology in which the latter itself is a program of control theory.