% One needs PDF2SVG to generate the SVG graph.
% Update Date: 11/16/2014

\documentclass{amsart}
\usepackage[paperwidth=400px, paperheight=200px, top=-10px, left=0px, right=0px, bottom=0px]{geometry}
\usepackage{amsmath,amssymb,nopageno}
\usepackage[all]{xy}
\begin{document}
\Huge
\def\coker{\mathop{\rm coker}}
\[
	\xymatrix{ %Our diagram is a 5x7 matrix
	&  & \ker a \ar[r] \ar[d] & \ker b \ar[d] \ar[r] & \ker c \ar[d] 
	\ar@{-} `/4pt[rr] `[dd]^d `^d[llll] `^r[dddd] &  &  \\
	&  & A \ar|\hole^(0.3)a[dd] \ar^f[r] & B \ar|\hole^(0.3)b[dd] \ar^g[r] & C \ar|\hole^(0.3)c[dd] \ar[r] & 0 &  \\
	&  &  &  &  &  &  \\
	& 0 \ar[r] & A' \ar[d] \ar^{f'}[r] & B' \ar[d]  \ar^{g'}[r] & C' \ar[d] &  &  \\
	\ar[rr] & & \coker a \ar[r] & \coker b \ar[r] & \coker c &  &  
	}
\]
\end{document}