There are a lot of difficult achievements in "Frost Age 2", and not having a final design is one of them. To do this achievement, you need to switch a law to its opposite, and then switch it back again. You know what to think, it’s a process of switching, but don’t take switching as a commitment.
What to do if there is no final design achievement in Ice Age 2
No final design
Switch a law to its opposite and back again.
Be careful not to switch as part of a promise, otherwise you will lose trust when switching back.
Location: Story or Utopia Builder
You might get this by going back and forth trying to appease one faction and then another.
If not, it's pretty simple.
Within the same subcategory, the pattern changes back and forth, for example:
Under society-->Funeral
Harvest Funeral Pass - 10 weeks later
Rite of passage funeral - 10 weeks later
Harvest the Funeral Pass - Achievements Unlocked
There is No Final Design
Change a policy to another one, and then pass the previous one once again
Location: Story or Utopia Builder
You will likely obtain this by going back and forth trying to appease one faction and then another.
If not it's fairly simple.
In the same sub-category change laws back and forth for example:
Under Society --> Funerals
Pass Harvesting Funerals - 10 weeks later
Pass Ceremonial Funeral - 10 weeks later
Pass Harvesting Funerals - Achievement unlocked