A favorite passtime for those with lots of time to pass, its right up there with watching dogs ####.
Usually someone will say "I see a cat" or what ever and other will say "yes, I see that". But occasionally someone will say "I see this" and others will ask for more information, trying to figure out what they are seeing, sometimes telling them how ####ed up they are.
If you have ever sat with me during an animal cloud evening you have probably heard me tell the joke of Maxwell Smart (agent 86) going to the therapist (sorry no link to the exact episode but here is a reminder).
The therapist shows Max an inkblot and Max says, "its a man and a woman kissing".
The therapist shows him the next one, Max says "its a man and a woman kissing".
The therapist shows Max a third ink blot to which Max replies "its a man and a woman kissing".
The therapist says "you seem to have a preoccupation with sex". Max says "me! your the one with the dirty pictures"
Around the same era Barney gives Otis the inkblot test