$\Newextarrow{\xhookrightarrow}{10,10}{0x21AA}$
3.62
\begin{equation} \label{equation:pushout-aux-1} \begin{gathered} \xymatrix@R =50pt@C=50pt{ Y' \ar [r] \ar [d] & X' \ar [d] \\ Y \ar [r] & X. } \end{gathered} \end{equation}