[592] Which is that form (rūpa) that is internal (ajjhattika) and impinging (sappaṭigha)?
The eye sense base (cakkhāyatana) … the body sense base (kāyāyatana) — this is that form that is internal and impinging.
Which is that form that is external (bāhira) and impinging?
The form sense base (rūpāyatana) … the tangible-object sense base (phoṭṭhabbāyatana) — this is that form that is external and impinging.
Which is that form that is external and non-impinging (appaṭigha)?
The femininity faculty (itthindriya) … edible nutriment (kabaḷīkāro āhāro) — this is that form that is external and non-impinging.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.