@Deusovi @Deusovi I know cryptics use specific signal words for things. is the pattern "(thing) extracts (foo) from (bar)" constrained to signal that (foo) is in fact being taken from (bar), or is there latitude to have it mean something other than the straightforward reading?
huh. that didn't do what i thought it would at all.
@Rubio There's always latitude for thigs to be different. I've seen traditional anagram indicators being used for definitions. But typically, cryptic indicators are read as English instructions, so that would be a valid interpretation.
My original answer failed to take advantage of the certainty that the number of bars on each window was strictly even, so cost me an extra day. I fixed it after Joe posted a more complicated strategy that actually amounted to the same thing.
A few other people provided answers that accepted zero bars as a possibility, but I excluded that from the beginning.
People started jumping in with complicated graphs showing the deep-knowledge trees and what-not. I expressed it quite simply and with provable correctness using the basic strategy I first used, simplified with your notation. Thanks for that, btw - the shorthand came in useful ;)
It took me 4 separate read-throughs of Joe's solution to finally convince myself it was correct, but I promptly pointed to his as the right answer. Once I figured out why it was right, I amended mine to show it only required knowing that the numbers were even, to make it work.
Heh. I noticed, only when I copy-pasted it in for my final version. At that point it wasn't worth calling attention to :)
The best part -
once OP switched the checkmark to Joe's, and he got a couple more votes, I got myself a Populist Badge out of the deal. So it worked out well for me ;)