# [Octave], 144 bytes Summary of changes: - The third character must be one with a codepoint lower than 60. For ASCII, that means: `' !"#$%&'()*+,-./0123456789:;'`, or tab. - The following characters can only be used five times in total: `!"#$.[\]`. --- <!-- language-all: lang-matlab --> <pre><code>.6;%+->?|"e"|?>-+%;6. f=@(x)all(ismember('Hi, Retina!',x))&sum(ismember(x,cat(2,33:36,46,91:93,'')))<6&x(3)<60 % </code></pre> [Try it online!][TIO-jezlhyj2] **Satisfies:** 1. The first character is a `.`. 2. Its length is an even perfect square. 3. Contains the exact sequence `->`. 4. Contains the exact string `Hi, Retina!`. 5. The second character's Unicode code point, mod 5, is 4. 6. The 10-th character is a `"`, and so is the twelfth character (palindromic rule). 7. The last non-empty line does not have any duplicate characters. 8. The first line is a palindrome of length = 21 9. It contains a `?`. 10. It contains a `|`. 11. It contains a `+`. 12. It is at least 28 lines long. **For future answers:** - [Octave]: https://www.gnu.org/software/octave/ [TIO-jezlhyj2]: https://tio.run/##lVXdbts2FL7PU3BsbJKJzJjyz2KpktOhfwECDOiCAIPjdoxMJUopSpXkzE5dYFdDH6E3e4jd72q53Fv0RTLKovzTZhtG27J4vvMnnY/nJEHBb8T9Pe27jf2WP1xAARdDv7XfcPt0J/SO8IxwKXGUxyK@EBlGLyMLvBJFpPg3yJoR0syn8RqeWQEvsG11Ok6nb3X71oA5g46FECHkcb85wx39195p7PzHuk/fsw/AA@ipFVpHFkPuTvreLiUjRCmhFFmAtS2AKDmOVxtIoUfRuNTtGN0a@vzLb0JUUNdAndEjhMSNUONK3jPytmiDJANpFqkCS6FwpNJpgQnZ26O9BvO8NqkM@sZAfDjnOb39gXWAXr0K/NaA/CKYiPDyKrp@K2OVpO@yvJje/Dyb36IqMx9AH9Zp@uC4DPZEypXEB@zzx4/2xv77aaF1QGcpWgY7rFNv@bfuzMsEn5xESuSYuHPvTARFkkW3Ak@L8PA0OVYF0WV1uZrjy0ykEsOWD8taVpkPjLOW3/5ps9pLkLUNylr@BgiOgYzeCvA8Eyq4As7TZW7AQvDVmZTuhF45XE1Api9JDPQbCENQJEntlNVOWbOJc8@HG651bs1mPhqMPQ8hqJlkbGo2MCnlix/PXkKY3n3asrv7469f6d6fv1evDt19et3eNcY1PZgLXbYiyfkXcd3dN95j3w2uktRd0gHMDw4OAr/XbGaaOFkuakvxbveNa3zX/Do9Pj15BiCHj/QPPDvR@zVtJ7zg9SZyaBhJCeyexax2Lc0dmhc66CWADbs3en2uxiuaFGtsqwxGAYVr/Lu5@BKllzK54BLEPFJGVN46YL2MOJ3mVxLsRtvb3GwD3RlAHnAVGgGfTDR8aIGGyNOHXVQ2RabP1ZZRd8son16AXZuVMj4zsutbMN/2GW76XNYn/Bef13EKVkHnzrar4n@5EsqpK5GJwpS9bh9Mcxwztgch3GMMTxRfE2yLXvo1ax1SqkseX0w4yB04XNU4UiCvuV53GkarpQll7ta@tTt9JvloI8Z4jQ1HLWZ3MV34nAxX8u5gda7rfrUYVh@4D83dQocon3o7eWQNrI5dAptfBOp@Z9zWnanvQsH1gNGHQY8XLqCeL6u2/TWD9ePHaZIVIJ/ntWTdkLVQ83sSKVp2OkxonsqowPBcQUJ8u7/PiDbSrS3Ww6hMzOoyUgZalAtWj9OltslxsMrx6xlYB39oFG7NwgeG4T@MQt3CSt31OKzyaSBrM2O7T3R2eo2Yo6axkDglbiCkDKcKH@GAgFBfLJCS8f3f "Octave – Try It Online"