A puzzle of surpassing awesomeness: thanks Oyler. I was wary of it at first, because more than one legitimate solution means that it won’t be possible to complete it by deduction alone, and I don’t like having to guess. But as I worked through it, I could pin enough of it down to make some progress, and as it came gradually to a halt there was enough of the message emerging to see what was happening. It helped that I was listing the possible answers for the clues that could be narrowed down, and gradually eliminating the possibilities, and couldn’t help noticing something striking about the values that were left in many cases… and then the penny dropped :-) Very neatly done.