The affixes ktavā and ṇamul are added to the roots kṛ 'to make' and bhū 'to be', in composition with a word denoting a member of one's own body when the affix tas is joined thereto.,
The word स्वाङ्ग has already been defined in sutra 3.4.54. The svanga word in the present case must be such as should end in the affix तस् - a taddhita affix technically called तसि and तसिल् 5.3.78 &c)). Though here there are two roots कृ and भू, and there are two affixes to be applied i. e. क्त्वा and णमुल्; yet the rule of 'respective allocation' 1.3.10 does not apply here. Both the affixes are applied to each of the roots. Thus मुखतः कृत्य गतः or मुखतः कृत्वा गतः or मुखतः कारङ्गतः । Similarly पृष्टतःभूय तिष्ठति or पृष्टतः भूत्वा तिष्ठति or पृष्टतः भावं तिष्ठति ।
Why do we say 'a word denoting a limb of one's own body'? Observe सर्वतः कृत्वा गतः ।
Why do we say 'ending in the affix तस्'? Observe मुखीकृत्य गतः, मुखीभूय गतः ।
Why do we use the word 'the affix'? If तस् is not an affix, but a verb, the rule will not apply. Thus मुखे तस्यति = मुखतः 'throws in the mouth'. With this मुखतः so formed, we cannot apply the rule. Thus मुखतः कृत्वा गतः ।,