  A closed discrete subset $A\subset \mathbb{C}$ is called tame if
$\mathbb{C}\setminus A$ is quasiconformally equivalent to $\mathbb{C}\setminus
\mathbb{Z}$. By giving several criteria for $A$ to be tame, we shall show that
$\mathbb{Z}+i\mathbb{Z}$ is not tame.
