Blue always answers a question truthfully; a White always 
lies; a Pink, answering two or more questions, tells the 
truth and lies alternately; his first answer, however, may 
be either truthful or otherwise. 

A visitor to the islands approached a group of three natives, 
whose names were Mr. Pink, Mr. White, and Mr. Blue.  One was 
known to be a Pink, one a White, one a Blue.  Taking Mr. Pink 
aside, the visitor put some questions to him. 

"Mr. Pink," he said, "are you the Pink, the White, or the Blue?" 

"I am the Pink, sir." 

"And Mr. White?" 

"He is the White." 

"So Mr. Blue is the Blue?" 

"Obviously." 

Is Mr. Blue the Blue? If not, what is he?
 

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                  THE SOLUTION

1. Mr. Pink is not the Blue; for if he were, he would say so.
2. Mr. Pink is not the Pink.  For if he is, his first answer
   is truthful.  But if his first answer is truthful, his
   third answer is truthful also.  Now, however, his second
   answer is likewise truthful; which is impossible.
3. So Mr. Pink is the White.  It follows that all his answers
   are untruthful.  Mr. White is the Blue, and Mr. Blue is
   the Pink.