The position of 'last' in sentences

My post on another site has prompted me to ask this question. What is the rule of using 'last' in a sentence?

For instance:

When did you revise this rule last?

When did you last revise this rule?

I last revised this rule three days ago.

I revised this rule last three days ago.

I revised this rule three days ago last.

I revised last this rule three days ago. _{(I think here it is at a wrong position)}

Are there any other possible versions?

When did you revise this rule last?

This is fine.

When did you last revise this rule?

Also fine.

I last revised this rule three days ago.

Also fine.

I revised this rule last three days ago.

This is understandable, but unusual, and might depend on spoken stress on "last" to make it sound right. In writing it would not work well.

I revised this rule three days ago last.

This is not fine, and might not be properly understood.

I revised last this rule three days ago.

Also not fine, and this would definitely mark you as a non-native speaker, although the meaning would be understood.