@function ballistic-flatten($list, $shallow: false) {
  $result: ();

  @each $item in $list {
    @if type-of($item) == "list" {
      @if $shallow {
        @each $_item in $item {
          $result: append($result, $_item);
        }
      } @else {
        @each $_item in ballistic-flatten($item) {
          $result: append($result, $_item);
        }
      }
    } @else {
      $result: append($result, $item);
    }
  }

  @return $result;
}