Complex alignments of blocks

Question

How could the kind of layout below be achieved in LaTeX, without using a letter document class?

At first, I thought of tables, but it would be impossible to align the first line of the second block with the last one of the first block.

Thank you for any help or reference.

Answer 1

\noindent
\begin{minipage}[b]{3cm}
1\\2\\3\\4\\5
\end{minipage}%
\hfill
\begin{minipage}[t]{3cm}
\begin{minipage}[b]{3cm}
3\\4\\5
\end{minipage}\\
6\\7
\end{minipage}