“Fly” perception exercise

I came across an old post here recently that described a perception exercise that involved the word FLY in caps, white on black.

Im assuming people are meant to see different things on viewing but nobody explained what these were.

Has anyone come across this before?

Ta

James

I came across an old post here recently that described a perception exercise that involved the word FLY in caps, white on black.

Im assuming people are meant to see different things on viewing but nobody explained what these were.

Has anyone come across this before?

Ta

James