Mind Bending 'Grass Pants' Optical Illusion Stumps the Internet

An optical illusion that looks suspiciously like a pair of pants made from grass has confused the internet.

In a viral picture shared on Reddit's popular r/confusing_perspective forum, user Flimsy_Researcher wrote: "Those are not grass pants" alongside the mind-bending image.

With over 18,000 upvotes and hundreds of comments, the image has sparked conversation and interest.

Joseph Brooks, Ph.D., a senior lecturer and director of research for psychology, Keele University, U.K., told Newsweek: "The visual system typically uses a range of contextual information and even default assumptions of what it typically encounters (e.g., I see trees at a distance more often and thus I'll assume that this is the case) to resolve the ambiguity of the situation.

"For instance, if there were other objects in the scene (e.g., a road leading up to the tree) or something overlapping the tree, this would suggest it is farther away. If the tree were overlapping something else, then this might suggest that the tree is closer. The size would then be adjusted accordingly. This works well much of the time."

But, explained Brooks, who has particular interest in visual perception and attention, it is that same contextual information that can cause misleading visual illusions.

"Lack of contextual information presents an ambiguity that needs to be resolved through assumptions about depth and how the scene is illuminated."

In the image that looks a lot like a pair of pants made from grass, the subject is standing looking through a window with grass or green carpet on the other side—because of the dark color of the pants and bright flooring behind, the reflection causes us to see a snapshot of both sides of the glass—making it look as though the grass is on the clothes.

Viewers on Reddit took to the comments to discuss the illusion, and one comment said: "Took me way too long to work this one out," while another user wrote: "I'm staring at it for a solid minute now and still can't. Care to help me out?"

Another commenter was amazed by how the visual trick suddenly became apparent and said: "It's amazing how these go from completely alien to frankly obvious."

One viewer joked it was: "Reverse greenscreen," and another wrote: "I know they aren't, but if they were grass pants I would put them on whenever I mowed my lawn."

Last week, another illusion that looked like the Star Wars death star wowed the internet.

Newsweek has reached out to Flimsy_Researcher for comment.