I wrote a snippet of code to get a beautiful cuboid but it looks a little distorted. I'd be glad if someone can infuse beauty into the output.
(I am sorry if the question is too localised; feel free to (vote to) close if you consider so.)
\documentclass{amsart}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{tikz}
\usetikzlibrary{matrix,arrows}
\newcommand{\Z}{\mathbb Z}
\begin{document}
\begin{tikzpicture}
\matrix (m) [matrix of math nodes, row sep=0.5em,
column sep=2em]{
&\Z/30\Z& \\
\Z/15\Z&&\\
&\Z/10\Z& \\
&&\Z/6\Z \\
\Z/5\Z&& \\
&\Z/3\Z& \\
&&\Z/2\Z \\
&\{1\}& \\};
\path[-]
(m-1-2) edge (m-2-1)
edge (m-3-2)
edge (m-4-3)
(m-3-2) edge (m-5-1)
(m-2-1) edge [-,line width=6pt,draw=white](m-6-2)
edge (m-6-2)
(m-2-1) edge (m-5-1)
(m-8-2) edge (m-5-1)
edge (m-6-2)
edge (m-7-3)
(m-7-3) edge (m-4-3)
(m-3-2) edge (m-7-3)
(m-4-3) edge [-,line width=6pt,draw=white](m-6-2)
edge (m-6-2);
\end{tikzpicture}
\end{document}







