text: import scadnano as sc
  
  
  def create_design() -> sc.Design:
      helices = []
      num_helices, max_bases = 30, 2000
      for _ in range(num_helices):
          helices.append(sc.Helix(max_bases))
      design = sc.Design(helices=helices, strands=[], grid=sc.square)
  
      return design
  
  
  if __name__ == '__main__':
      d = create_design()
      d.write_scadnano_file(directory='output_designs')
  