Natyashastra
वामं सूचीपदं दद्यादपक्रान्तञ्च दक्षिणम् । भुजङ्गत्रासितं वाममतिक्रान्तं च दक्षिणम् ॥ १२॥
The left foot should perform the Sūcīpadam (needle-like movement), followed by the Apakrānta (sideward movement) to the right. Then, the Bhujangatrāsita (serpent-like) movement should be executed with the left foot, followed by the Atikrānta (upward movement) to the right.
english translation
vAmaM sUcIpadaM dadyAdapakrAntaJca dakSiNam । bhujaGgatrAsitaM vAmamatikrAntaM ca dakSiNam ॥ 12॥
hk transliteration by Sanscript