Kerodon

$\Newextarrow{\xRightarrow}{5,5}{0x21D2}$ $\newcommand\empty{}$
$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
4.47
\begin{equation} \begin{gathered}\label{equation:silly-diagram-for-fun} \xymatrix@R =50pt@C=50pt{ A \times _{\operatorname{\mathcal{C}}} \operatorname{\mathcal{D}}_0 \ar [r] \ar [d] & B \times _{\operatorname{\mathcal{C}}} \operatorname{\mathcal{D}}_0 \ar [d] \\ A \times _{\operatorname{\mathcal{C}}} \operatorname{\mathcal{D}}\ar [r] & B \times _{\operatorname{\mathcal{C}}} \operatorname{\mathcal{D}}} \end{gathered} \end{equation}