  Homoclinic classes of generic $C^1$-diffeomorphisms are maximal transitive
sets and pairwise disjoint. We here present a model explaining how two
different homoclinic classes may intersect, failing to be disjoint. For that we
construct a one-parameter family of diffeomorphisms $(g_s)_{s\in [-1,1]}$ with
hyperbolic points $P$ and $Q$ having nontrivial homoclinic classes, such that,
for $s>0$, the classes of $P$ and $Q$ are disjoint, for $s<0$, they are equal,
and, for $s=0$, their intersection is a saddle-node.
