begin at the end of the spectrum
then add the numeral ten
next find our personal pronoun
and stick it on the end

(In reply to some thoughts by K Sengupta)

First line: "begin at the end of the spectrum."

We know that:
"Newton divided the spectrum into seven named colors: red, orange, yellow, green, blue, indigo, and violet (this order being popularly memorized by schoolchildren using the mnemonic ROY G. BIV)."

Source: http://en.wikipedia.org/wiki/Visible_spectrum

Conclusion: Red is indeed at the end of the visible spectrum.

It may also be noted that:

"Purple is a general term for the range of shades of color occurring between red and blue.........In color theory, a 'purple' is defined as any non-spectral color between violet and red.[3] The spectral color violet is not a purple."

Source: http://en.wikipedia.org/wiki/Purple

Conclusion: Purple can be regarded as a shade of red

Second line: "then add the numeral ten"

It is widely known that  "X" is the roman numeral for ten.

Third line: "next find our personal pronoun"

We know that the objective personal pronoun for "we" is "us".

Thus, in conformity with first through fourth lines, we now have: "purple" + "X" + "us" = PurpleXus, which is phoenitically similar to "perplexus".

Consequently, the required answer to the riddle is "perplexus".

Posted by K Sengupta on 2009-01-31 12:30:39