A block diagram focuses on the input and output of a system. It is less concerned with what happens between input and output. In engineering, this is known as the black box principle. The parts that get us from information to output are either unknown or unimportant. Block diagrams are created in the same way that flowcharts are. You'll want to make blocks, which are frequently represented by rectangular shapes representing important points of interest in the system from input to output. The relationship between these components will be demonstrated by connecting the blocks with lines. Block diagrams make use of simple geometric shapes such as boxes and circles. The main parts and functions are represented by blocks connected by straight and segmented lines that depict relationships.