docs: def run_all(plot=True, seed=None):
      """ Run all examples. """
      if seed is not None:
          import random
          random.seed(seed)
  
      print("Running biggest_multiple.py")
      biggest_multiple.run(plot=plot)
  
      print("Running polynomials.py")
      polynomials.run(plot=plot)
  
      print("Running travelling_salesman.py")
      travelling_salesman.run(plot=plot)
  
      print("Running irrigation.py")
      irrigation.run()