Apastambagrihyasutra 7.18.10

7.18.10

pariṣecanāntaṃ kṛtvā vāgyatassaṃbhārānādāya prācīmudīcīṃ vā diśamupaniṣkramyasthaṇḍilaṃ kalpayitvā tatra prācīrudīcīśca tisrastisro lekhā likhitvā 'dbhirupaninīya tāsūttarayā saktūnnivapati \10\

Having performed (the rites) down to the sprinkling (of water) round (the fire), he silently takes the objects required (for the rites which he is going to perform), goes out in an easterly or northerly direction, prepares a raised surface, draws on it three lines directed towards the east and three towards the north, pours water on the (lines), and lays (an offering of) flour (for the serpents) on them, with the next (formula, II, 17, 8).