[626] Which is that form (rūpa) that is internal (ajjhattika) and not lightness of form (rūpassa na lahutā)?
The eye sense base (cakkhāyatana) … the body sense base — this is that form that is internal and not lightness of form.
Which is that form that is external (bāhira) and lightness of form (rūpassa lahutā)?
That which is lightness of form, its quick transformability, non-sluggishness, non-inertness — this is that form that is external and lightness of form.
Which is that form that is external and not lightness of form?
The form sense base (rūpāyatana) … edible nutriment (kabaḷīkāra āhāra) — this is that form that is external and not lightness of form.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.