$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
4.47
\begin{equation} \begin{gathered}\label{equation:silly-diagram-for-fun2} \xymatrix@R =50pt@C=50pt{ A \times _{\operatorname{\mathcal{B}}} \operatorname{\mathcal{C}}\ar [d]^{j} \ar [r] & \operatorname{\mathcal{D}}\ar [d]^{V} \\ B \times _{\operatorname{\mathcal{B}}} \operatorname{\mathcal{C}}\ar@ {-->}[ur] \ar [r] & \operatorname{\mathcal{E}}. } \end{gathered} \end{equation}