16: [Quarterstaff](https://github.com/Destructible-Watermelon/Quarterstaff), 64
===

-1 is truthy,


    .1......."a".......1.
       1->a[Hi, Retina!]
      ?[-124(.|>a)?]
    49a!

[Try it online!](https://tio.run/##KyxNLCpJLSouSUxL@/9fz1APApQSlaAsQz0uBQUFQ127xGiPTB2FoNSSzLxExVigoH20rqGRiYZejV2ipn0sl4lloiKyCXpkmQAA "Quarterstaff – Try It Online")

the indentation doesn't do anything, by the way.

**Satisfies:**

2. The first character is a `.`.
3. It contains an `e`.
4. Its length is even.
5. Its length is a perfect square.
6. It contains an `a`.
7. It contains a `>` character.
8. Contains the exact string `->`.
9. Contains the exact string `Hi, Retina!`.
10. The sum of the first two Unicode code points is a multiple of 5.
11. The 10-th character is a `"`.
12. The last non-empty line does not have any duplicate characters.
13. The first line is a palindrome of length > 5.
14. The first line is exactly 21 characters long (not including newline).
15. It contains a `?`.
16. It contains a `|`

**For future answers:**

- The first character is a `.`.
- Its length is an even perfect square.
- Contains the exact sequence `->`.
- Contains the exact string `Hi, Retina!`.
- The second character's Unicode code point, mod 5, is 4.
- The 10-th character is a `"`, and so is the twelfth character (palindromic rule).
- The last non-empty line does not have any duplicate characters.
- The first line is a palindrome of length = 21
- It contains a `?`.
- It contains a `|`