You are playing the Regex Pattern Matcher game against o1 - (high).

Game history:
Turn 1: o1 - (high) proposed text with target items: ["user+label@subdomain.example.org","user.name@domain.co.uk","+1 (555) 456-7890 ext. 123","+49 (0)30-1234-5678","02/29/2020","2020-02-29","29.02.2020","192.168.0.1","fe80::0202:B3FF:FE1E:8329","https://www.example.com/path/to/page?query=stuff&param=morestuff","ftp://user_123:pa$$@ftp.example.com:21/some%20folder","https://sub.domain.com:8080/path?param=value#anchor","123-45-6789","ABC-123-xyz","A123B-999"]
Mistral Nemo (12B) provided pattern: ^[^\n]*(?=.{21,41}$) (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 patter... (truncated)