input: 
  def sierpinski_triangle(n):
      """
      Generate the first n elements of the Sierpinski triangle.
      Each element is a row of 1s and 0s representing the structure of the Sierpinski triangle.
  
      >>> sierpinski_triangle(6)
      ['1', '1 1', '1 0 1', '1 1 1 1', '1 0 0 0 1', '1 1 0 0 1 1']
      """
  
output:     if n == 0:
          return []
      result = ['1']
      for i in range(1, n):
          prev_row = result[-1]
          new_row = ['1']
          for j in range(1, len(prev_row)):
              new_row.append('0' if prev_row[j-1] != prev_row[j] else '1')
          new_row.append('1')
          result.append(' '.join(new_row))
      return result