رَأَيْتُ أَحْمَدَ
Translation: I saw Aḥmad.
رَأَيْ: past-tense verb built on sukūn with the attached subject tāʾ.
تُ: attached pronoun in the nominative position as subject.
أَحْمَدَ: accusative direct object with visible fatḥa and no tanwīn.
Compare «رَأَيْتُ زَيْدًا»: Zayd is also accusative, but it takes tanwīn; Aḥmad does not.