Pāṇini sūtras

The Participial affix vas (vas) gets the augment iṭ only then when the reduplicated root before it consists of one syllable, or when it comes after a root ending in long ā, and after ghas

1. vasuवसु

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   vव्	vasuवसु	vasuवसु	vasवस्	vasवस् + plus uउ

2. eka+a+c+ā+t+ghasāmएक+अ+च्+आ+त्+घसाम्

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   eए	ekaएक	ekaएक	one	ekaएक
   aअ	aअ	aअ	akāraअकार	aअ
   cच्	cच्	cच्	CC	cच्
   āआ	āआ	āआ	ākāraआकार	āआ
   tत्	tत्	tत्	TT	tत्
   gग्	ghasघस्	ghasāmघसाम्	ghasघस्	ghasघस् + plus āmआम्

Anuvṛtti

1. va+l+ādeḥव+ल्+आदेः 7·2·35

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   vव्	vaव	vaव	vakāraवकार	vव् + plus aअ
   lल्	lल्	lल्	LL	lल्
   āआ	ādiआदि	ādeḥआदेः	first syllable	ādआद् + plus eḥएः