Abdulmotaleb Amara, Other, Libya
I hope without a picture the idea will be clear:
The idea is based by creating two managers for the firm, the first one is the chairman and he's responsible for the supporting departments such as finance and accounting, HR, etc., the second manager is the executive manager who is responsible for the core business of the firm, such as marketing & sales, projects, or any other core function relating to the firm's business. This second manager is reporting to the chairman.
When we draw a chart, it seem vertical departments (supporting departments) report to the chairman are serving the the core business while the horizontal departments report to the executive manager.
Hope it is clear?