[eatnumber1]

For the impossible bullets, they link to informal arguments as to why it's impossible. The ruby one has code - it's a syntax error.

[GuiA]

The bullets link to non-solutions, which are not enough to formally prove that it is impossible to solve this challenge in the language.

[eatnumber1]

Agreed. These are informal. If you want to make a formal proof that it's impossible, I'll make a new category.