Does water flowing over other limbs while performing ablution (wudu') under a shower affect the validity of the ablution?

If water moves from one limb to another limb among the limbs of ablution, this does not affect the validity of the ablution, because this water is not considered used. Shaykh Taqiyy al-Din said: "As long as the water is flowing over the body of the one performing ghusl and the limb of the one performing wudu' in a continuous manner, it is not considered used until it separates." Even if the water were considered used, purification with it is sufficient according to many scholars.