my @bar = @foo [map {$_ + ($_ % 2) * -2 + 1} 0 .. $#foo];

# Destroys the array. Doesn't work in situ.
my @bar; push @bar, reverse splice @foo, 0, 2 while @foo;

# Doesn't work in situ.
use List::MoreUtils ':all';
my (@bar, @t);
my $i = natatime, 2, @foo;
push @bar, reverse @t while @t = $i->();

# Doesn't work if there's an undefined value on an even position.
my @bar = do {my $t; map {defined $t ? do {my $x = $t; undef $t; ($_, 
+$x)} : do {$t = $_; ()}} @foo};
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