You fly 500 km north, 500 km east, then 500 km south and 500 km west. Will you arrive at the departure point?

No, the plane will not reach the departure point, since the flight path will not be a square, but a trapezoid.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.