text: module.exports = function towelSort(matrix) {
      if (!matrix || !matrix.length) return [];
  
      let res = [];
  
      for (let i = 0; i < matrix.length; i++) {
          let arr = matrix[i];
          if (i % 2) arr = arr.reverse();
          res = [...res, ...matrix[i]];
      }
  
      return res;
  };
  