Kryptos means hidden in Greek, The Sculpture...(in my opinion) it is a piece of artwork and is designed to hide the element of human curiosity from the final solution. The solution to Part 4 of the sculpture is hidden from view...in the absence/illusion of light. My guess is that the morse codes found around the sculpture are the final clues when factored in with the other three solutions. Its like a riddle. My first guess tho was that this sculpture had multiple purposes as does all art. First there are many literary transpositions, most important of all is the first sentence. That is the plot, The morse codes are partially hidden and partially complete. "T is your position" alluding to "what? is you position". Second Mistakes were made and hints were given away, "berlin=NYPVTT" My last and final interest is to measure the the shadow cast by the statue based on a four point compass to SEE if the shadow falls onto a CLUE or object during the day and at night. The obvious answer to PART 4 has to do with BERLIN and all the other solutions references. The key is the cipher! Also the four quadrants (squares) of the sculpture could reference to a geometric cipher, I was always intrigued by this statue/sculpture and its reference to the word hidden! (Its a Geometric Cipher)(Something only an Artist could make) on a side note I myself use it as a (public key) HINT! Its was meant to be private. No public eyes! anyways thats were I'm at I haven't bothered finding which geometric cipher was used i'm guessing a private one.