Time, la, and prepositions

[janKipo]

We all know pretty much how to do time expressions using 'tenpo' and 'la' and whatever else is relevant, but the usage has not been codified beyond a few examples, There are also some time concepts that are not obviously covered by what we have so far. Further, there is a desire (maybe even a need) to shift some time expressions from the condition slot to the preposition slot or to use complex time expressions as modifiers. This an attempt to spell what I think we all agree about and to point to some few hints of a way forward.
tenpo la sometime(s), not never, not always, generally not even regularly
tenpo lili la rarely, occasionally
tenpo mute la frequently, often, generally
tenpo [nanpa] la [nanpa] times (with pini or kama to say if all occurrences are in one direction or the other)
tenpo suli la for a long time, hence: ? [add awen? aa}
tenpo lili la for a short time, briefly X aa
tenpo pini la (at some time) in the past, past tense
tenpo kama la (at some time) in the future, future tense
tenpo suno/pimeja pini la yesterday/ last night, on a past day (also with (tenpo) sike suno, (tenpo) sike mun and tenpo esun)
tenpo suno/pimeja kama la tomorrow/ tomorrow night, on a day in the future
tenpo suno pini tu wan la three days ago ? (similarly for pimeja and kama and other numbers)
tenpo suno tu wan pini la after three day, three days later ? (etc.)
tenpo suno tu wan la for/during three days ? (etc) aa
tenpo suli pini la a long time ago ? (etc.)
tenpo la for a while X aa
I think I am forgetting some time expressions here, but this is as far as I can find even hints of usage.
For prepositions there are not a lot of usage, but the pattern seems to be x la goes unchanged to lon x for those that point to a particular time or times. For those involving a duration, the obvious thing is to replace the tense word (pini or tawa) at the end with a preposition at the front, but which one gets tawa and which tan is open to a long argument. And the "for a" cases don't seem to fit anywhere, though you will note a suggestion above.

[janMato]

Seems like some of these could be collapsed into a few rules, some seem lexical.

kama implies the future is moving towards us. pini only really says "finished", but if events in the future are moving towards us, where do they go as they move past us? Do they zag off to the left? So I think toki pona is a FUTURE IS AHEAD, PAST IS BACK language. Which makes it a rather garden variety in this respect, but less auxlangy than it could be- if I recall correctly, Chinese is an time is up/down system. Maybe if the word "sin" or "open" had been chosen for future time, the entire directed-time-line metaphor could have been avoided.

by characteristic of such time, "tenpo pimeja la", but also "tenpo pi moku mute la" feast time/at the party

time without kama/pini is either forward or backwards in time, "tenpo ensun la" a week ago/in the future, "tenpo suli la" a long time in the future/past

numbered time = duration

calendar time by any of the calendar proposals = point in time.

tenpo pi tenpo sike akesi la jan lili lili suli li kama. In the year of the Dragon a great premature baby was born.

And the rest are lexical, e.g. "tenpo la" to mean "for a while" would need a dictionary lookup.

And a final note-- while writing my example, I noticed it felt necessary to have two tenpo's to make a duration clear.

tenpo pi tenpo suno la mi tawa ala tomo pali. A day ago, I didn't go to work.