"outside" vs. "outside of"

[Milanya]

Is there any difference between the usage of "outside" and "outside of"? It seems that they are both used in quite the same contexts.

For example, in American Corpus these examples are quoted:

1.1. Outside town, the morning brightens as a curtain of sunlight flows into the valley
1.2. Outside of town he pushed the Ford to sixty and let it ride.

2.1 He thinks outside of the box.
2.2 A bunch of narrow-minded car distributors didn't know how to think outside the box.

Is there any perceivable difference between the two, or they are intercgangeable ?
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con·text - The part of a text or statement that surrounds a particular word or passage and determines its meaning.

[Mister Micawber]

Interchangeable, I think, Milanya. I would call the one with 'of' slightly less formal, merely in terms of style.
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Native English teacher at Mister Micawber's

[Milanya]

Thank you ever so much, Mister Micawber. Your help is invaluable.
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con·text - The part of a text or statement that surrounds a particular word or passage and determines its meaning.