Yesterday I put ChatGPT, Claude and Gemini in a group chat. Now I want Reddit to break it

Yesterday, my post about forcing ChatGPT, Claude, and Gemini into a roundtable discussion to fact-check eachother got way more traction than I expected. The idea is simple: use the diversity of three AI models to catch hallucinations. If OpenAI misses a logical leap, Anthropic or Google catches it. But some of the sharpest comments here pointed out the ultimate failure mode: What if all three models share the exact same training blind spot? So instead of defending the setup, I want you to help me break it. Give me a question, problem or prompt that you think ChatGPT, Claude AND Gemini will all get wrong. It could be an obscure factual trap, a very convincing false premise, a common coding misconception, or a logic puzzle where the internet consensus is wrong. The part I'm especially curious about is whether: 1. One model catches a mistake immediately 2. They fight and eventually figure it out 3. Or all three confidently agree on the same wrong answer For context, this is the multi-model discussion setup I've been building into Rauno, but I'm mainly interested in finding its failure cases here. Give me your best attempt on a question to break it and I'll reply if they actually caught each others hallucinations.