Structograms can be divided into two (from release 3.27 on: three) categories:
 main programs (as in any sequential programming language),
 subroutines (procedures, functions, methods),
 includable diagrams (only versions ≥ 3.27)
Main programs are drawn with square corners whereas sub methods are drawn with rounded corners. Depending on the type of diagram you chose and whether your diagram is boxed or not, the diagram is drawn differently.
The type of a diagram can be chosen via the menu or by using the speedbuttons:
The following table resumes all cases by giving an example:
Type 
Speedbuttons 
Diagram 
main, boxed



main, not boxed



sub, boxed



sub, not boxed



Note:
 The type of the diagram (main or sub) usually influences the source code generator and may thus result in different code.
 Only diagrams of type sub (and includable) are callable, i.e. may be employed by the executor if referenced in a Call element (also see Program/Sub).
 As visible in the images above, the heading of an unboxed diagram will appear in gray whereas the box of a boxed diagram is white (unless being selected or marked as testcovered, of course).
