http://www.perlmonks.org?node_id=1055042


in reply to Explaining small Code

In split, it is explained that split; defaults to split ' ', $_;.

\@numbers is not de-referencing but is creating a reference to the array @numbers. So @matrix will be an array of array references. Without it, the push would push all individual elements of @numbers onto @matrix, effectively creating a long one-dimensional list instead of a matrix.