i think there are 2 scenario
1) you have 14 thread and 14 activity --> you need to write at lest 14 threads in the period to reach, after 14 days, 28 activity and 28 posts...
2) you have 140 thread and 14 activity --> you need to write at least 1 thread in the period to reach , after 14 days, 28 activity and 141 posts.
I'm not sure if i understand your way.. Here you have two scenarios:
Ok. So to clarify: 
It is possible to get 140 activity points in 10 - two weeks periods (20 weeks), but there must be minimum one post in every two week period and sum of all posts must be 140 or more? yep?
It is possible to get 140 activity points in 10 - two weeks periods (20 weeks), but there must be minimum one post in every two week period and sum of all posts must be 140 or more? yep?Correct. You can also collect it another way. Say if you made 140 posts in this two week period you could just make one post in each new period and you would then collect the full 14 points up to 140.
