Thanks for creating this task as I requested, but now that I have considered and experimented with this (and having been enthusiastic to follow through), I concluded it would unnecessarily complicate our simple DWDS logic gate. I found that any of the Boolean logic gate possibilities can be handled with additional sentences -- e.g. a sentence for MUST, and a sentence for MUST NOT. Using all the NAND and XOR and XNOR stuff would significantly reduce comprehensibility for the majority of users, and would complicate our overall data model, to obtain results that can already be expressed with a bit of thought. I found that I had to invest MORE thinking into using XOR correctly than I required to contrive of a way to express the same thing with our original system. And in doing so, the end result would complicate both human rule-taker understanding and RuleTaker app design.