  We define an inhomogeneous percolation model on "ladder graphs" obtained as
direct products of an arbitrary graph $G = (V,E)$ and the set of integers
$\mathbb{Z}$ (vertices are thought of as having a "vertical" component indexed
by an integer). We make two natural choices for the set of edges, producing an
unoriented graph $\mathbb{G}$ and an oriented graph $\vec{\mathbb{G}}$. These
graphs are endowed with percolation configurations in which independently,
edges inside a fixed infinite "column" are open with probability $q$, and all
other edges are open with probability $p$. For all fixed $q$ one can define the
critical percolation threshold $p_c(q)$. We show that this function is
continuous in $(0, 1)$.
