# 21. [Alphuck], 676 bytes

*Surprisingly, most of the code is not padding.*

    .11111111"1"11111111.
    ?|+->Hi, Retina!opaos
    iipiiciasceaecppisaic
    sapiceasccpisipiiiiia
    ecsaiiijaeepiiiiiiaec
    saeeejeepiiiaeecsajee
    eeeepiaeecsaejipiiiii
    iaecsaijeeeeeeeeeejii
    iiiijiipiiiaecsaijiii
    piaeeeecsaijeejiiijii
    iiiiiiiiiiijiipiiiaec
    saijiipiaeeeecsaejiii
    iiiiiiijeeeeeejiiijpi
    iaeeeeecsaeeejpiiaeee
    eeeecsajeejiiijiiiiii
    iijeeeeeeeeeeejeeepia
    eeecsaeejeeeeeeeeeeee
    jpiaeeeeecsaijepiaeee
    csaeejeeeeeeeeejiiiii
    iiiiijiipiiiaecsaiiij
    epiiiiaecsaeeejiipiae
    eeecsaijepiaeeecsaeje
    eeeeeeeeeejiiiiiiiiii
    iijiipiiiaecsaiijpiae
    eecsaejipiaeeecsajiii
    piaeeeecsajiiiiiiiiii
    ijeeejiiiiiiiijejiipi
    iiaecsajpHenry Jams?a
    bcefghiwklmnopqrstuvw
    xyzabcdefghwuklmnopqr
    stuvwxyzabcdefg~

[Try it online!][TIO-jezv2lpw]

**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 `|`.
17. Contains a `+`.
18. It is at least 28 lines long.
19. The following characters are used five times in total: `!"#$.[\]` and the codepoint of the second character is less than 60.
20. Contains `Henry Jams?` as a continuous substring.
21. The last character is `~`.

<hr>

**For future answers:**

- The first character is a `.`, and so is the 21st character (palindromic rule).
- The 10th character is a `"`, and so is the 12th character (palindromic rule).
- The first line is a palindrome of length 21.
- The second character's Unicode code point, mod 5, is 4, **and** its code point is lower than 60 (the printables are `',1;6` and tab).
- The last character is `~`.
<hr>

- Its length is an even perfect square.
- It is at least 28 lines long.
- The last non-empty line does not have any duplicate characters.
<hr>

- Contains the exact sequence `->`.
- Contains the exact strings `Hi, Retina!` and `Henry Jams?`.
- It contains `|` and `+`.
<hr>

- Each program is now allowed only the 2 `.` and 2 `"` in the first line, and the `!` in `Hi, Retina!`. Those characters cannot be used anywhere else, in addition to no uses of `#$[\]`.

[Alphuck]: https://github.com/TryItOnline/brainfuck
[TIO-jezv2lpw]: https://tio.run/##7VJBUsMwDLzrFYUr0Bk@QK8djvxANYJKbVNRN4QyDF8vsmUnaV7AocolWu2uV4lxq@s2bM7n@WOpW3tKzWHxc/fwtOT72QsducGbveI@ArMyB8YYCCmockQOEFHZgBiCAYlhhUDBhsyCRA6xSYxLROKQvRrHGjDMEO9JigUkgXkI9SUJTaY5SJ0nblZT5YtzgIcaJOCaQZHplSv9SSyaM1SWgZpDe16PXk7yvOOoacm0E1T1eEYgOjibzDuYEKX6Tle2FvyrYo3mC8HEMW/neceWfd4LUykO9ScUg8n3vXCQsaV4CiiGoktqDqfZM@7iAmEV6O19zd1mu2v2@nGIx/azg6/TN67Caxp1bR1Bng2j3@stvd7S/39L/wA "Alphuck – Try It Online"