A riddle can be eternal.Logical formLearned from19 sentences. A book can be constituted-of-or-filled-with riddles.Logical formLearned from18 sentences. A riddle can be to a person.Logical formLearned from18 sentences. A male can be a riddle.Logical formLearned from17 sentences. A riddle can be relative to women.Logical formLearned from17 sentences. A riddle can be global.Logical formLearned from17 sentences. An enigma may be wrapped in a riddle.Logical formLearned from17 sentences. A key can be to a riddle.Logical formLearned from16 sentences. A riddle can be famous.Logical formLearned from16 sentences. (Picture riddles) may undergo a collection.Logical formLearned from16 sentences. A riddle can be simple.Logical formLearned from16 sentences. A riddle can be philosophical.Logical formLearned from16 sentences. A riddle can be simple.Logical formLearned from16 sentences. A riddle can be complex.Logical formLearned from16 sentences. Riddles may pertain-to the universe.Logical formLearned from16 sentences.