Chat with our AI personalities
In navigation, by air and sea craft.
A fjord is a real world example of a fjord! They exist in the real world.
There is no real world flat surface which goes on forever. It is a geometric idealised concept. So, since there is not even a first such thing, there cannot be another.
If you are asking about periodic function in the real world, than there are millions of examples. The first one that comes to mind are the sin and cos functions. These are used in almost every field of science.
You cannot. It is a fiction, a story line in a movie.