Samyutta Nikaya: Rahulasamyutta (II-18)
1 – 8: Takes us through the six sense and their realms, understanding them as impermanent and therefore the cause of suffering:
eye forms eye-consciousness eye-contact feeling-born-of-eye-contact
perception of forms volition regarding forms craving for forms
Each of these is applied to one of eye, ear, nose, tongue, body, mind.
9: The same applied to earth, water, heat, air
10: The same applied to the five skandhas.