There are four troll brothers - Wudhor, Xhaqan, Yijlob, and Zrowag.
- Wudhor always says the truth.
- Xhaqan always lies.
- Yijlob lies or says the truth unpredictably.
- Zrowag is deaf and never answers.
You must ask these brothers only four questions (one troll per question), and figure out which of them is who. What questions would you ask?