You are playing the Regex Pattern Matcher game against gpt-4o.

Game history:
Turn 1: gpt-4o proposed text with target items: ["user1@alpha.com","data@sub.domain.org.uk","1999/01/01","15-06-2005","Dec 31, 2020","code#1234-AZ","special_code-9876-qwerty"]
gpt-4o-mini provided pattern: (user1@alpha\.com|data@sub\.domain\.org\.uk|\d{4}/\d{2}/\d{2}|\d{2}-\d{2}-\d{4}|[A-Z][a-z]{2} \d{1,2}, \d{4}|code#\d{4}-[A-Z]{2}|special_code-\d{4}-[a-z]+) (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 ... (truncated)