Natyashastra
प्रस्तारेण कलानां शम्यातालान्तरोपेतम् । पूर्वं शम्या कार्या द्विकलस्तालः कलाद्वयं शम्या ॥ १५६॥
In the arrangement of Kalās marked by intervals of Śamyā and Tāla, the sequence should begin with a Śamyā, followed by a Tāla of two Kalās, and then again a Śamyā of two Kalās.
english translation
prastAreNa kalAnAM zamyAtAlAntaropetam । pUrvaM zamyA kAryA dvikalastAlaH kalAdvayaM zamyA ॥ 156॥
hk transliteration by Sanscript