Let's say you get your tiles and you can spell "VALLEY". Is it legal to play "ALLEY" your first turn and then add the "V" your second turn? Assuming no double word score squares or anything, you would end up with 20 points over 2 turns instead of 12 in 1 turn. Would it really be worth it (obviously in this example it's not a very high-scoring word, but you get the idea)?