BUR #51574 has been approved by @nonamethanks.
mass update favgroup:49573 -> figure-ground_illusion
create implication figure-ground_illusion -> optical_illusion
a tag for images that look different when you recognize different parts of the image as being part of the background instead of part of the foreground
https://en.wikipedia.org/wiki/Figure%E2%80%93ground_(perception)
