  For a fixed root of a quiver, it is a very hard problem to construct all or
even only one indecomposable representation with this root as dimension vector.
We investigate two methods which can be used for this purpose. In both cases we
get an embedding of the category of representations of a new quiver into the
category of representations of the original one which increases dimension
vectors. Thus it can be used to construct indecomposable representations of the
original quiver recursively. Actually, it turns out that there is a huge class
of representations which can be constructed using these methods.
