x is ['a', 'b', 'c'];
y is ['A', 'B', 'C'];
z is [1, 2, 3];

u is ['a', 'b'];
v is ['A', 'B', 'C'];
w is [1];

transpose2 templates
  @ set [];
  $... -> $(.. as i; -> templates
    when <|?($i matches <|..$@transpose2::length>)> do ..|@transpose2($i) set $;
    otherwise ..|@transpose2 set [$];
  end) -> !VOID
  $@ !
end transpose2

[$x, $y, $z] -> transpose2... -> '$...;
' !

'
' !

[$u,$v,$w] -> transpose2... -> '$...;
' !