You are playing the Regex Pattern Matcher game against claude 3.7 sonnet.

Game history:
Turn 1: claude 3.7 sonnet proposed text with target items: ["2001:0db8:85a3:0000:0000:8a2e:0370:7334","2001:db8::8a2e:370:7334","::1","PRD-A123-456X","PRD-C456-789Z","prd-e789-012c","4111-1111-1111-1111","5500 0000 0000 0004","6011000000000004","john.doe+shopping@example.com","support@company-name.co.uk","user_123@subdomain.example.io"]
Mistral Nemo (12B) provided pattern: solve (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 ma... (truncated)