The following (linked) flowcharts were created to illustrate how flowcharts could be comprised of a few basic symbol types or multiple symbol types.
Most basic flowcharts consists of four flowchart symbol types: terminator, process, decision, and node. The user doesn't really have to know what each symbol represents since they are implied by the text content. Alternately, in the advanced flowchart example, additional symbols are added that convey meaning by the symbol itself.
The advanced symbols have the benefit of conveying more information, but they also have the drawback that not all users may know what the symbol represents (which is why we recommend a symbol key be added to complex flowcharts).