An optical illusion shows two sets of apparently distinct chess pieces.
The photograph has gone viral after being uploaded on Twitter by scientific writer Tom Chivers.
In a foggy setting, the illusion reveals white and black chess pieces.
The supposedly white set is in a predominantly black smoke atmosphere, while the seemingly black is in a generally lighter smoke setting.
While the two sets of chess pieces seem different, they're really identical—each piece is the same as the one below it. Their appearance is deceptive.