Nested control flow statements CASxx, DO, DOU, DOW, DOUxx, DOWxx,
FOR, IF, IFxx, MONITOR and SELECT are often key ingredients in creating what’s known
as "Spaghetti code". This code smell can make your program difficult to understand and maintain.
When numerous control structures are placed inside one another, the code becomes a tangled, complex web. This significantly reduces the code’s
readability and maintainability, and it also complicates the testing process.
