Natyashastra
तर्जनीमध्यमाङ्गुष्ठास्त्रेताग्निस्था निरन्तराः । भवेयुर्हंसवक्त्रस्य शेषे द्वे सम्प्रसारिते ॥ १०४॥
Haṃsāsya (swan-beak)—the forefinger, middle finger and the thumb close to one another and the remaining fingers stretched.
english translation
tarjanImadhyamAGguSThAstretAgnisthA nirantarAH । bhaveyurhaMsavaktrasya zeSe dve samprasArite ॥ 104॥
hk transliteration by Sanscript