Ok, I don't get it. It's a random guess? There doesn't seem to be any
logic I can use to intuit the correct color. Am I just dense, or do you
have to assume that the pattern is a coherent one and use an "educated"
guess?
I like Brian's answer to this question. I'll add, in case it's not
obvious, that each pattern was designed by a human pattern-designer,
whose goal is to make a fun game experience. So you can assume that
you'll be able to make better and better "educated guesses" as more and
more of the pattern gets revealed.
Notice that, as in Zendo, it's possible to design patterns that are too
obscure or difficult, in which case the player's guesses will continue
to feel somewhat random throughout the game. I've designed patterns that
I knew would be good, solvable patterns, without even having to playtest
them, but I've also tried some designs where I've thought "I'm not
really certain whether people can figure this out." A few of those
patterns worked fine, but many of them failed. Again, as with Zendo,
it's taken me a while to develop my intuition about how to make good
patterns.
-- Kory