तस्य द्विरथोत्तरा वृद्धिरैकविंशतिरथादिति ॥ कZ_१०.५.१५ ॥
tasya dvirathottarā vṛddhir aikaviṃśatirathād iti
De esa (formación estándar), el incremento se hace añadiendo dos carros cada vez, comenzando desde veintiún carros.
Even-number increments preserve bilateral symmetry (left/right) and keep wings balanced while scaling the formation.
A minimum viable baseline size for this formation family, from which standardized expansions are authorized.