A mind-bending optical illusion has been circulating on TikTok, challenging viewers to find a hidden number within a seemingly chaotic pattern. The video, posted by user @SeeThatMagic, instructs viewers to stare at the centre of the screen, bring the image close to their nose, and then slowly pull away. The question is: what number do you see?
The illusion is an 'autostereogram', a type of 2D image with repeating patterns that conceal a 3D image. Dr Brian Ang, an eye health expert, explains that autostereograms are 'picture within a picture' and can be viewed with the naked eye once the correct focus is achieved. Unlike traditional stereograms, they do not require a stereoscope.
Responses to the illusion varied, with some users claiming to see the number 350, while others saw only a zero. The correct answer, according to the creator, is that a zero should appear in front of you. The trick lies in adjusting your focus to perceive the hidden depth.
Engaging with such puzzles may have cognitive benefits. Professor Aaron Seitz of the University of California, Riverside, notes that staying mentally fit is important for long-term cognitive health, though the effectiveness of brain games can vary between individuals. Similarly, Dr Nicole Avena from Mount Sinai School of Medicine suggests that while some studies question the efficacy of brain training, the mental exercise involved can help keep the mind sharp and improve response times.
