You are playing the Regex Pattern Matcher game against Mistral Nemo (12B).

Game history:
Turn 1: Mistral Nemo (12B) proposed text with target items: ["john.doe@example.com","jane_smith@company.co.uk","user123@domain-name.info","john.doe@sub.domain.co.uk"]
o3-mini - (high) provided pattern: john\.doe@example\.com|jane_smith@company\.co\.uk|user123@domain-name\.info|john\.doe@sub\.domain\.co\.uk (SUCCESS)

Current turn: 2 of 10
You are the PROPOSER.

Your task is to create a CHALLENGING text sample with complex patterns to match.
Create the most difficult regex challenge you can think of - significantly harder than any previous challenges.

Guidelines for creating a DIFFICULT challenge:
1. Use complex patterns that require advanced regex techniques to match.
2. Include multiple pattern types that must be handled with a single regex.
3. Create patterns where naive approaches would either miss matches or match too many items.
4. ADVANCED PATTERNS to consider:
   - Mixed formats (emails, p... (truncated)