my @arrayA;
my @arrayB;
while (...) {
   @arrayB = ...;
   push(@arrayA, \@arrayB);  # XXX
}

##</code><code>##

my @arrayA;
my @arrayB;
while (...) {
   @arrayB = ...;
   push(@arrayA, [ @arrayB ]);  # Ok
}

##</code><code>##

my @arrayA;
while (...) {
   my @arrayB = ...;
   push(@arrayA, \@arrayB);  # Ok
}

##</code><code>##

my @arrayA;
while (...) {
   my @arrayB = ...;
   push(@arrayA, [ @arrayB ]);  # Needlessly creating 3rd array.
}