त्रीणि त्रिकाण्यनीकं रथानामुरस्यं स्थापयेत्तावत्कक्षं पक्षं चोभयतः ॥ कZ_१०.५.१२ ॥
trīṇi trikāṇy anīkaṃ rathānām urasyaṃ sthāpayet tāvat kakṣaṃ pakṣaṃ cobhayataḥ
One should set the chariot array as three triads; establish the center-front accordingly, and likewise the flanks and the wings on both sides.
Modular composition: building a larger array from repeatable triads to simplify control, alignment, and scaling.
To enforce symmetry so that the formation does not develop a structurally weaker wing, which would be exploitable.