Natyashastra
भुजङ्गत्रासितैर्भ्रान्त्वा पादैरपि च मण्डलम् । पिष्टकुट्टं च विज्ञेयं चारीभिर्मण्डलं बुधैः ॥ ६६॥
By performing the movements with a fear like that of a serpent, and using the feet as well, the form becomes a circle. The scholars recognize this as the "Pishtakutta" formation, which is performed with a variety of movements.
english translation
bhujaGgatrAsitairbhrAntvA pAdairapi ca maNDalam । piSTakuTTaM ca vijJeyaM cArIbhirmaNDalaM budhaiH ॥ 66॥
hk transliteration by Sanscript