Given a plane continuum $X$ and an annulus $A\subseteq\mathbb{R}^2$, we say that $X$ $A$-inscribes a polygon $P$ if every essential embedding of $X$ into the annulus $A$ contains a similar copy of (the vertices of) $P$. In this talk we will present conditions on $X$ that guarantee that $X$ $A$-inscribes squares for some fixed annulus $A$. Moreover, we will analyze how ubiquitous this property is among continua that separate the plane.