The document discusses constants in Ruby programming. It notes that constant names start with capital letters and can be overwritten with warnings. It provides some constant name samples and encourages trying out different Ruby versions. It also discusses making Ruby scripts confusing by using Unicode characters and constant names that are difficult to understand for future maintainers.

1. MAKE YOUR RUBY SCRIPT
CONFUSING
SATOSHI TAGOMORI (@TAGOMORIS)

2. CONSTANT

3. DO YOU UNDERSTAND
ABOUT CONSTANT
IN RUBY?

4. Constant
Name
starts with capital alphabetical letters
can be overwritten (with warnings)

5. Samples...

6. (Re) Constant
Name
starts with capital alphabetical letters
can be overwritten (with warnings)

7. Try some Ruby versions!

8. Nobu did it (as always)
Feature #13770:
"Can't create valid Cyrillic-named class/module"
http://d.hatena.ne.jp/nagachika/20180410/ruby_trunk_changes_63127_63130
https://bugs.ruby-lang.org/issues/13770

9. What I did:

10. rb_enc_isupper()
"UPPER" in Onigmo

11. UnicodeData.txt
http://ftp.unicode.org/Public/UNIDATA/UnicodeData.txt

12. List "CAPITAL" "LETTER A"
from UnicodeData.txt using Ruby
Try this script ...

13. "A" with something above

14. "A" with something below
"A" with something above & below

15. "A" with something on left shoulder
"A" with something on right
"A" with something on both

16. "A": something interesting
https://emojipedia.org/tag-latin-capital-letter-a/

17. ENJOY MAKING RUBY SCRIPT
CONFUSING!

18. "Always code as if the guy who ends up
maintaining your code will be a violent
psychopath who knows where you live."
-- John F. Woods
https://groups.google.com/forum/#!msg/comp.lang.c++/rYCO5yn4lXw/oITtSkZOtoUJ
https://stackoverflow.com/questions/876089/who-wrote-this-programing-saying-always-code-as-if-the-guy-who-ends-up-maintai