[michael_j_ward]

>They prevent other companies from creating their own "generics" through a process called "evergreening" where they change patents in small, insignificant ways while still maintaining the patent on the core product.

To be really clear:

1) A company receives patent X in 2000, which expires in 2020.

2) In 2018, that company gets a new patent Y that is really patent X but with "small, insignificant" changes.

Are you saying that after step 2, that original patent for X is now extended or will that still go generic in 2020?

[rayiner]

Not just the original patent, but every invention embodied in the original product will go into the public domain.

[michael_j_ward]

You are saying that step (2) has no effect on patent X from step (1), and thus patent X still enters public domain in 2020, correct?

Note- I understood this to be your position from your other comments. I asked the clarifying question to understand `pdeuchler`'s idea of the `evergreening` process.