Guessing from the three hammers you're either supposed to destroy the three statues that don't fit the riddle, or you get three chances to find a key in a statue that matches the riddle. Though the latter would likely mean whatever is in the chest isn't as worth it.I'll try to guess what the riddle is: You have to inscribe what a statue with the 4 combined traits would look like. So, wings, horn, claws and sharp teeth.