Natyashastra
हस्तपादप्रचारस्तु द्विकलः परिकीर्तितः । चतुरश्रे परिक्रान्ते पाताः स्युः षोडशैव तु ॥ १४४॥
The movement of the hands and feet is considered to consist of two kalas (measures). When the square is traversed, there should be sixteen falls.
english translation
hastapAdapracArastu dvikalaH parikIrtitaH । caturazre parikrAnte pAtAH syuH SoDazaiva tu ॥ 144॥
hk transliteration by Sanscript