Sometimes a motion, sometimes the sound associated with that motion against a flat surface – and when Gollum flaps, it seems to be both motion and sound in one image.

• 04.018 keeping time with the flap of their flat feet on the stone,
• 04.044 Soon they could hear even the flap of the goblin feet,
• 05.056 He flapped into the water
• 05.089 and flapped back to his boat,
• 08.005 Bilbo tried flapping his hand
• 08.006 flapping and whirring round their ears.
• 15.013 slowly flapped his wings,