Consider the following tikz code
\begin{tikzcd}[column sep=20pt]
A \arrow{rr}\arrow{dr} && B && C \arrow{ll}\\
& D \arrow{dr}\arrow{ur}\\
&& E \arrow{urur}
\end{tikzcd}
The problem I am facing is that the arrows of D to B and E to C are not parallel (the arrow from B to C being too short). I think the problem comes from the fact the node C is not specified as belonging to a fourth column.
Hence, for example, A is in column 0 (no &), D is is column 1 (&), B and E are in column 2 (&&), but so is C. Yet, if I am trying to specify a column 3 (&&&), I am getting an error message. What am I doing wrong?
(Alternatively, if I could just manually change the length of the arrow from B to C, that will do too!)