code: def cross_product_compare(start, candidate1, candidate2):
      
      delta1 = candidate1 - start
      delta2 = candidate2 - start
      return cross_product(delta1, delta2)
docs: Compare two relative changes by their cross-product.
  
      This is meant to be a way to determine which vector is more "inside"
      relative to ``start``.
  
      .. note::
  
         This is a helper for :func:`_simple_convex_hull`.
  
      Args:
          start (numpy.ndarray): The start vector (as 1D NumPy array with
              2 elements).
          candidate1 (numpy.ndarray): The first candidate vector (as 1D
              NumPy array with 2 elements).
          candidate2 (numpy.ndarray): The second candidate vector (as 1D
              NumPy array with 2 elements).
  
      Returns:
          float: The cross product of the two differences.