I'm crafting an extremely challenging regex puzzle that combines multiple advanced patterns. The target items include: complex email addresses with multiple '+' signs and intricate subdomains; international phone numbers with country codes, varied separators, and optional extensions; dates expressed in three formats that cover leap-day edge cases (YYYY-MM-DD, DD/MM/YYYY, MM.DD.YYYY); alphanumeric codes that require the first and third groups of letters to be identical (a natural candidate for ba... (truncated)