  A class of Laplacian growth models in the channel geometry is studied using
the formalism of tripolar Loewner evolutions, in which three points, namely,
the channel corners and infinity, are kept fixed. Initially, the problem of
fingered growth, where growth takes place only at the tips of slit-like
fingers, is revisited and a class of exact exact solutions of the corresponding
Loewner equation is presented for the case of stationary driving functions. A
model for interface growth is then formulated in terms of a generalized
tripolar Loewner equation and several examples are presented, including
interfaces with multiple tips as well as multiple growing interfaces. The model
exhibits interesting dynamical features, such as tip and finger competition.
