Greetings!
Here are my thoughts about the 16 steps:
1) the first tetrad appears to mean experiencing the bodily fabrication (breathing) and experiencing the calming/stilling of bodily fabrications;
2) the second tetrad appears to mean experiencing the mental fabrications (bodily and mental feelings and perception of feelings) and experiencing the calming/stilling of mental fabrications (perceptions of feelings together with piti and sukha?);
3) the third tetra appears to mean experiencing the states of the unliberated mind and experiencing the state of the temporarily liberated mind;
4) The 4th tetrad (contemplation of the Dhamma) seems to mean contemplating anicca (Aniccānupassī, ) / dispassion (virāgānupassī) / cessation (nirodhānupassī) / nibbāna (paṭinissaggā = nibbāna). For how to contemplate these, please see Vipassana taught by the Buddha [
http://www.dhammawheel.com/viewtopic.ph ... 56#p301456]. It's interesting to note that the methods for virāgasaññā and nirodhasaññā are similar in Girimānandasuttaṁ sutta (The Discourse to Girimānanda). I suppose that the method for paṭinissaggāsaññā is also similar.
Katamā c' Ānanda aniccasaññā? [01]
Now what, Ānanda, is the perception of impermanence?
Idh' Ānanda bhikkhu araññagato vā, rukkhamūlagato vā,
Here, Ānanda, a monk who has gone to the wilderness, or to the root of a tree,
suññāgāragato vā, iti paṭisañcikkhati:
or to an empty place, considers thus:
rūpaṁ aniccaṁ
form is impermanent
vedanā aniccā
feelings are impermanent
saññā aniccā
perceptions are impermanent
saṅkhārā aniccā
(mental) processes (volitions) are impermanent
viññāṇaṁ aniccan-ti.
consciousness is impermanent.
Iti imesu pañcasupādānakkhandhesu aniccānupassī viharati.
Thus in regard to these five constituent groups (of mind and body) that provide fuel for attachment he dwells contemplating impermanence.
Ayaṁ vuccat' Ānanda aniccasaññā.
This, Ānanda, is called the perception of impermanence.
"Katamā c' Ānanda virāgasaññā? [06]
Now what, Ānanda, is the perception of dispassion?
Idh' Ānanda bhikkhu araññagato vā, rukkhamūlagato vā,
Here, Ānanda, a monk who has gone to the wilderness, or to the root of a tree,
suññāgāragato vā, iti paṭisañcikkhati:
or to an empty place, considers thus:
Etaṁ santaṁ, etaṁ paṇītaṁ,
This is peaceful, this is excellent,
yad-idaṁ:
that is to say:
sabbasaṅkhārasamatho,
the tranquilising of all processes (volitions?),
sabbūpadhipaṭinissaggo,
the letting go of all bases for cleaving (the relinquishing of all attachments?),
taṇhakkhayo,
the end of craving,
virāgo,
dispassion,
Nibbānan-ti.
Nibbāna.
Ayaṁ vuccat' Ānanda virāgasaññā.
This, Ānanda, is called the perception of dispassion.
Katamā c' Ānanda nirodhasaññā? [07]
Now what, Ānanda, is the perception of cessation?
Idh' Ānanda bhikkhu araññagato vā, rukkhamūlagato vā,
Here, Ānanda, a monk who has gone to the wilderness, or to the root of a tree,
suññāgāragato vā, iti paṭisañcikkhati:
or to an empty place, considers thus:
Etaṁ santaṁ, etaṁ paṇītaṁ,
This is peaceful, this is excellent,
yad-idaṁ:
that is to say:
sabbasaṅkhārasamatho,
the tranquilising of all processes (volitions?),
sabbūpadhipaṭinissaggo,
the letting go of all bases for cleaving (the letting go of all attachments?),
taṇhakkhayo,
the end of craving,
nirodho,
cessation,
Nibbānan-ti.
Nibbāna.
Ayaṁ vuccat' Ānanda nirodhasaññā.
This, Ānanda, is called the perception of cessation."
[From
http://www.ancient-buddhist-texts.net/T ... ram-20.htm, with my notes in parentheses]
Just my two x two cents. Metta to all!