DB<100> @AoA = (
               [11,29, 10,25],
               [15,35, 11,29],
               [15,15, 11,21],
               [10,25, 11,21]
              )

  DB<101> @flat = map { @$_ } @AoA
 => (11, 29, 10, 25, 15, 35, 11, 29, 15, 15, 11, 21, 10, 25, 11, 21)