"Obvious" is in the eye of the beholder. And most computers don't have "eyes" at all.
I think this site demonstrates that the only thing a computer has over a human brain is speed and persistence. Granted, one could program the 'search' differently and much more 'intuitively' as well as more 'human' like, but that would simply show how much 'brain' power is needed for a 'blind' brain to solve a visual problem.
Next time, try solving the puzzle with your eyes closed!
I also suspect that the 'solving' portion of the code is intentionally slowed down or at least manipulated to indicate the 'thoroughness' of the 'computer.' After all, the puzzle is 'generated' rather quickly. Assuming that they are actually unique puzzles, the same general plan is followed for generating as well as solving; the 'generating' part must be sure that the puzzle is solvable in one and only one way. The 'solving' display is probably slowed down so the human watching can actually see something going on!
As I intended to say above, computers are fast, but not as well endowed with multiple senses and intuition, not to mention experience!
It makes me feel better when I can figure out a solution before a computer can, even if the computer is intentionally 'crippled!' But it still upsets me when I keep telling my Mac to do something and it refuses simply because I'm not using the exactly correct command! "How stupid can this thing be?!"
Wonder if the computer is thinking the same thing...
JC
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"Don't anthropomorphize your computer, they hate that."