DB<104> @arr = qw/a b c/; 
 => ("a", "b", "c")

  DB<105> foreach ( "x",@arr,"y") {
              push @arr, 'd' if $_ eq 'a';
              push @arr, 'e' if $_ eq 'b';
              push @arr, 'f' if $_ eq 'c';
              print $_;
          }
 => ""
xabcy
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better rely on orthogonal behavior!