encode_string = String.new ''
      @text_parts.each do |str|
         @temp = String.new ''
         0.upto(@square.size - 1) do |i|
            str2 = str[@square[i]-1]
            if (str2.nil?)
               str2 = '_'
            end
            @temp.concat(str2)
         end
         encode_string.concat @temp
      end