First, having only two constants, 2 and an empty list, makes it inconvenient to use hard-coded values. If I want to use a specific vector (3, 0, 0) for every cast, I need to: make an empty list, add a 2 to it, get the length of that list, add 2 to that, and finally create a vector with the resulting three and two zeros I have to make by reading the length of more empty lists. A few more constants would be nice.

Second, a glyph made to function as… a variable (I guess?) for the more specialized types of casting. For example, when you attack with a tool or sword. The attacked entity is used as an “input” for the spell, but many ploys - likely what’ll be used in such a scenario - take multiple inputs, and there’s no way to specify where that entity is input (that I know of). A specific glyph that means “the input” could solve that issue.

Lists were not intended for acquiring an arbitrary number... that's a clever way of doing that! The lack of constants is intentional. There are many ways to create literal values from the number 2, which you may then save in any item, and later embed in a spell with only a single revision (see the end of the section on spell scribing). #62 will also add the possibility of easily referencing these constants when editing a spell, and it's getting pretty close to a state where it can be merged.

Regarding your second point, you may want to read the section in tricks/delusions-ingresses/arguments? I'm fairly sure it's what you're referencing here.

If you have any more questions, you're free to drop them here or ask in the Discord!

I get it now, though I wasn’t sure what those arguments actually meant from the book’s explanation.