text: module.exports = function towelSort (matrix) {
    let array = []; 
    if (matrix == undefined) return [];
    for(let i = 0 ; i < matrix.length; i++ ) {
      if (i % 2 == 0) { 
        array.push(...matrix[i])
      }
      else array.push(...matrix[i].reverse())
    }
    return array; 
  }
  