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The photo was taken with a time-lapse camera.
This type of camera can be set to take continuous pictures at fixed intervals, commonly used to record plant growth or changes in weather and clouds. It's very easy to operate; four size AA batteries can power it for up to 78 days.
In elementary school observation courses, such cameras are often used to teach students how to watch the process of seeds sprouting and growing.
Autumn Carter placed one of these cameras at the entrance of his house.
Purple Summers guessed that Autumn chose this location under the influence of some detective anime works.
Some murderers would quietly return to the scene of the crime after the dust had settled to retrieve something they left behind, eliminating future threats—based on this idea, Autumn had unwaveringly taken shots at his house's entrance for two years.
The persistence of a child can sometimes shame an adult.
