Thanks for your questions, I'll expand on the docs.
do any of the symbols have inherent meaning or functions?
They don't, there's really just two things in multiset rewriting, rules and symbols.
It looks like two of them are the same symbol as as the “run operation” and “undo” buttons, but when I use them they seem to operate exactly like any other symbol.
That's just so you can customize them :)
Still, some additional clarification on the notation system used here would be appreciated.
A line starting with :: indicates a rule, symbols are just names that could be shapes in tote, the caret(>) indicates the start of the right-hand side of the rule, that's it :)
Above are the rules for the subtraction operation, now if I put some things in the bag(8-3):
And press evaluation a few times, I get the result 5:
