Sāṃkhya Kārikā verse 30

yugapat-catuṣṭayasya tu vṛttiḥ krama-śaśca tasya nirdiṣṭā |
dṛṣṭe tathā-api-adṛṣṭe trayasya tat-pūrvikā vṛttiḥ ||

catur - fourtu - moreovervṛtti - fluctuation; modification; turning; set in motion, course of action, behaviour, movement; activity, function; professionkrama - sequence; order; series; regular arrangement; succession; progressing step by step; in regular course; gradually, by degreestasya - itsapi - even, also, very; something more; moreoveradṛṣta - unseentraya - the threetat - that, this