We discuss two examples of quantum systems with
interactions supported on lines located in a plane.
First, we analyze the model with  delta potential supported
on angle in $\R^2$. Our aim is to derive
the eigenvalues asymptotics if the angle-shape line approach to the
straight line.
Moreover, we study the system with potential supported on
two parallel lines and the eigenvalues asymptotics
is obtained if both lines approach to each  other.
Finally, discussed some generalizations of the above mentioned
systems.
The results presented in the talk are based on the common works with
P.Exner and D.Krejcirik.