On the morning of February 23rd, after washing up and eating, Chen Zhou pushed two tables together in front of the bedroom window and officially started piecing together the "Pure Blue Hell".
Having watched videos on restoring Pure White Hell before, he knew some restoration techniques for similar puzzles.
For example, you should first restore the frame.
In monochrome puzzles, the frame is the easiest to restore.
Every frame has a distinct feature, which is that it has a straight edge or a corner with a turn, making it noticeably different from the other pieces.
Moreover, the number of frame pieces is limited, so exhaustive attempts can be done quickly.
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Chen Zhou found a few wooden boxes and poured all the blue puzzle pieces from his backpack onto the floor, ready to carefully select and classify them.
The few kittens that didn't leave home last night heard the sound of puzzle pieces spilling on the floor and came over inquisitively.
