Sorry, I meant characters, not letters. Lol

"Did you intend to include the variable @& in that regular expression?"

No, it's not included in there. This regex is looking for something that starts with $ and is followed by one of the characters in the list. And @ and & happen to be in the list. But if a variable starts with @, it won't match. But now that I carefully looked at this part of the code, I noticed that if a character appears to be a variable but is not, then it gets eliminated from the double-quoted string instead of being left alone unchanged. I fixed that.

Today I tried to modify the code to replace variables like $^A, but this caused warnings to appear when running the obfuscated code, because for some reason $^A is treated almost like $a or $b (I have never used these variables ever and don't even understand what they are for) but they apparently don't need to be declared. But if I come up with a new variable such as $XX and start using it in place of $^A, then perl is going to say wait a minute, you didn't declare $XX anywhere in the code, you just started using it.