Hmph.

As I hinted at in my first paragraph, I actually started with that exact design (without es added rule - I'll get back to that) as my base. I found the same thing you did - it wasn't reasonably workable. Leave it to Erich Friedman to turn es computers loose on my prototype (three years later, no less) to find uniquely solvable instances anyhow... someone really needs to remind em that puzzles are supposed to be fun. (Actually, I'm not sure "remind" is accurate, as I'm not convinced e ever knew that...)

But what really makes es version bite the wax tadpole in my eyes is the rule e added that at least one bulb must be lit. Why e did that was obvious: all es puzzles would have a trivial additional solution otherwise - all bulbs off. Honestly, would using zeroes have killed em? Hello... hello, McFly... Needing to include a rule like that should be the first hint that there's something wrong with the design.

Thank you very much for this comment - you made my day. I'm glad you like my design better. I know I do... - ZM