2011 USAJMO Problems/Problem 4

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A word is defined as a finite sequence of letters. A palindrome is a word that reads the same forwards and backwards. Consider the sequence of words W0,W1,W2... such that W0 = a, W1 = b, and for all n >= 2, Wn is the word formed by writing W(n-2) followed by W(n-1). Prove that for all n >= 1, the word formed by writing W1,W2,...,Wn in sequence is a palindrome.