  This text is based on my talk at the popular science conference ``Dark
geometry fest'' which was related to geometric methods and their applications,
July 17, 2022. We will move towards the Smale-Hirsch theorem. To this end we
will deal with the simplest partial case of this theorem -- the
Whitney-Graustein theorem on regular curves in the plane.
  The text is written in an accessible and sometimes informal way, it is
intended primarily for people who are interested in mathematics, but have not
yet studied it deeply enough.
