physical stimulus remains stable while perception changes. In some famous ambiguous images, viewers can alternate between two recognizable objects. Hidden-image puzzles use a related idea, although one interpretation is intentionally made much more obvious at first. The challenge consists of discovering the less immediately accessible organization.
Social media has made puzzles of this kind especially easy to share because they invite participation without requiring specialized knowledge. A person can look at the image for a few seconds and immediately understand the challenge. Comments can then fill with people reporting how
