I'd ask him again and again to visualize the motion, to watch from within as the finger curled and extended, and to move along with it in his mind.
كنت أطلب منه مرارا أن يتخيل الحركة، أن يرى من داخله كيف يتحرك أصبعه ويتمدد وكيف يتحرك معه بعقله.