docs: def spheres_intersect(ar, aR, br, bR):
      """Return whether or not two spheres intersect each other.
  
      Parameters
      ----------
      ar, br: array-like, shape (n,) in n dimensions
          Coordinates of the centres of the spheres `a` and `b`.
      aR, bR: float
          Radiuses of the spheres `a` and `b`.
  
      Returns
      -------
      intersecting: boolean
          True if the spheres intersect.
      """
      return vector.vector_mag_sq(ar - br) < (aR + bR) ** 2