We consider measurable functions $f$ on $\mathbb{R}$ that tile simultaneously by two arithmetic progressions $α\mathbb{Z}$ and $β\mathbb{Z}$ at respective tiling levels $p$ and $q$. We are interested in two main questions: what are the possible values of the tiling levels $p,q$, and what is the least possible measure of the support of $f$? We obtain sharp results which show that the answers depend on arithmetic properties of $α, β$ and $p,q$, and in particular, on whether the numbers $α, β$ are rationally independent or not.