Natyashastra
शान्तितोयं ततो दत्त्वा ततः सूत्रं प्रसारयेत् । चतुष्षष्टिकरान्कृत्वा द्विधा कुर्यात्पुनश्च तान् ॥ ३३॥
After giving the water for purification (Shāntitoya), the performer should then stretch the thread. By making it with sixty-four strands, it should be divided into two parts, and then the same should be done again with those parts.
english translation
zAntitoyaM tato dattvA tataH sUtraM prasArayet । catuSSaSTikarAnkRtvA dvidhA kuryAtpunazca tAn ॥ 33॥
hk transliteration by Sanscript