grammar - Sentence in which "its" and "it's" can be interchanged without changing the meaning?

A friend posed the following word puzzle to me:

Can you think of a sentence that keeps the same meaning whether you use "it's" or "its"?

He asserted that this puzzle does in fact have a solution. However, it has me completely stumped. I tried to solve an easier problem, to find a sentence which is still grammatical if you change an "its" to "it's", but all I could come up with is examples like "It's light!" (which is, strictly, more of a sentence fragment).

What is the solution to the word puzzle? Or, is there some way I can "prove" that the puzzle should have no solution?

Answer

I gather from previous answers that there are two ways in which this question can go—either we interpret it strictly, and don't make assumptions about what it's asking, or we interpret it loosely.

If we interpret it loosely, we can bend the rules a bit:

• 
  

  As in the Hans Adler's answer, which I was picking on earlier, we can interpret "same meaning" more loosely. In this case, the solution works well (and I'm sure there are more that work even better) wherein one sentence indicates that you see the tree's apples, and one indicates you see that the fruit which the tree bears is the apple. We can also use a construction (I took this idea from another answer) like:

  
  

  
  

  "I cannot comprehend it's red." = "I cannot comprehend its red."

  
  

  
  


• 
  

  A sneaky solution can be to put "its" and "it's" in quotes in the sentence, to come up with something like:

  
  

  
  

  "I wrote a sentence with 'it's' and 'its' in it." = "I wrote a sentence with 'its' and 'it's' in it."

  
  

  
  


• 
  

  We can spell something incorrectly, as Hans Adler ironically points out in the most downvoted answer.

  
  


• 
  

  Or, as my girlfriend suggested, we can replace the "it" in the contraction "it's" with a proper noun (like that clever guy Stephen King did), making "it's" refer to something that belongs to someone or something named It. In this case the solution becomes again trivial, since "its" is also a possessive.

  
  

  
  

  "This clown is named It. It's nose is red." = "This clown is named It. Its nose is red"

  
  

  
  

(we sadly, in the last case, refer to a clown as an object, but it does have the same meaning)

Alternatively

All of these answers, to me, are trivial and make the puzzle somewhat boring. If we don't want the puzzle to be boring, we can't cut corners. In this case, as a few have pointed out, it is most likely impossible.