"We're a subreddit for things that, surprisingly and satisfyingly, fit perfectly into each other," the community writes.
We're talking window blinds that cast lines at the same degree as the handrail, bath mats that line up with the tiles, and musicians who merge perfectly with their instruments. You know, the good stuff.
Maybe it's the excitement of the unexpected that got 893k people to join this community. Or the soothing of their OCD. But whatever it is, it's working. And it's so damn fulfilling.
When you think about it, many of these satisfying perfect fit pictures could be described as... kind of dull. Uneventful. Especially on the Internet, a place where you can watch jaw-dropping "people are awesome" compilations and live footage from the Las Vegas wedding chapel cam.
However, that may be precisely the appeal, Jessica Gall Myrick, a media psychologist at The Pennsylvania State University, said.
"Even if you don't consciously realize you're stressed, your body is aware that you're stressed or physiologically aroused," Myrick told Live Science, using the scientific term for being in a state of high alertness. "That could drive you toward this type of soothing, interesting content."
There are plenty of alternative versions of this sort of relaxing, repetitive activity. Tibetan Buddhists, for example, spend hours painstakingly making colorful designs called mandalas out of sand, only to destroy them after they're done. It symbolizes the transitory nature of life.
Naturally, photos on your device don't have the tactile sensations of real-world activities, but it appears that they also do the trick.