The pattern is constructed as a union of several sub-patterns:
1. Emails: [a-zA-Z0-9.]+\+?[a-zA-Z0-9]+@[a-zA-Z0-9-]+\.[a-zA-Z.]+
   - Handles usernames with dots and plus signs
   - Matches domain with optional hyphens and multiple levels

2. Phone numbers: Three formats:
   - \+1-\(800\)-555-0199 (with country code)
   - 800\.555\.0199 (with dots)
   - \(800\) 555 0199 (with spaces)

3. Dates:
   - 2020-02-29 (YYYY-MM-DD)
   - 29/02/2020 (DD/MM/YYYY)
   - 15\.07\.2021 08:30 (with time)

4. Mirrored sequence: xyz-xyz
   - Using ([a-z]+)-\1 for exact mirror match

5. Complex ID: ABc-123-ABc
   - Using ([A-Za-z]+)-\d+-\1 with case-sensitive match

Each pattern is carefully constructed to match only the valid items and avoid matching invalid examples.