image = pdb.gimp_file_load('Desktop/waterfall.xcf', 'waterfall')
drawable = pdb.gimp_image_get_active_drawable(image)

for i in xrange(32):
  pdb.gimp_drawable_offset(drawable, True, False, 0, 16)
  layer_copy = pdb.gimp_layer_new_from_drawable(drawable, image)
  pdb.gimp_image_add_layer(image, layer_copy, 0)

gimp.Display(image)