docs: def get_bb_intersections(recording):
      """
      Get all intersections of the bounding boxes of strokes.
  
      Parameters
      ----------
      recording : list of lists of integers
  
      Returns
      -------
      A symmetrical matrix which indicates if two bounding boxes intersect.
      """
      intersections = numpy.zeros((len(recording), len(recording)),
                                  dtype=bool)
      for i in range(len(recording)-1):
          a = geometry.get_bounding_box(recording[i]).grow(0.2)
          for j in range(i+1, len(recording)):
              b = geometry.get_bounding_box(recording[j]).grow(0.2)
              intersections[i][j] = geometry.do_bb_intersect(a, b)
              intersections[j][i] = intersections[i][j]
      return intersections