Given a number n, print n-th Fibonacci Number
An immortal couple have been seen throughout recorded history, write an account of them in any time period you wish. Bonus points if you match the writing style of the time period.

In the waning days of the late fifteenth century, a curious tale unfurled in the quaint and mystical lands of Tuscany. It was a tale so peculiar, so beguiling, that even the most fervent devotees of the arcane could scarcely fathom the truths it concealed.

Deep amidst the verdant and secluded valley of the Arno, at the heart of the hallowed and resplendent Medici court, an enigmatic couple resided. Their names, whispered with a mixture of awe and trepidation,
What is the difference between mutex and critical section? Please explain from  Linux, Windows perspectives? 
I am programming in C#, would these two terms make a difference. Please post as much as  you can, with examples and such....
Thanks,
Robert
In the context of concurrent programming, both mutexes and critical sections are synchronization primitives used to ensure that multiple threads access shared resources in a controlled and safe manner. However, there are some subtle differences between the two.

A critical section is a region of code where access to a shared resource is mutually exclusive. It is a programming construct used to indicate to the compiler or runtime system that a certain block of code must be executed atomically, without interference from other threads. When entering a critical section, the thread acquires exclusive ownership of the critical section and prevents other threads from