I'm creating an exceptionally difficult challenge that combines multiple complex patterns:
1. IPv6 addresses (both full and compressed formats)
2. ISO-8601 date/times with optional fractional seconds and timezone offsets
3. Product codes with specific format requirements
4. "Fake" similar patterns that should not match
This requires handling:
- Complex alternation between different formats
- Variable-length components
- Careful boundary matching
- Negative lookahead to avoid false matches
- Prec... (truncated)