Manasara 6.24

6.24

maṇḍalāvadhideśe tu nītvā sūtrāṅgulaṃ nyaset
māsānāṃ paṅktipaṅkteśca divasānāṃ tridhā tridhā

Extending to the limit of the circle, he should lay down the digits of the cord; / of the months, decade by decade (paṅkti), and of the days, divided into three parts each,