code: def vortex(screenpos, i, nletters):  # noqa D103
      d = lambda t: 1.0 / (0.3 + t**8)  # damping
      a = i * np.pi / nletters  # angle of the movement
      v = rotMatrix(a).dot([-1, 0])
      if i % 2:
          v[1] = -v[1]
      return lambda t: screenpos + 400 * d(t) * rotMatrix(
          0.5 * d(t) * a
      ).dot(v)
  
imports: import numpy
  from moviepy import *
  from moviepy.video.tools.segmenting import find_objects
label_desc: Use image node_id 1 for calling a global function with example usage: vortex(screenpos, i, nletters) and returns: function