I was watching Seinfeld episodes, and came across the one where Elaine's boss was trying, without any success, to see whatever image was hidden in one of those 'magic eye' posters that were the rage in the late 1980's...and it brought to mind my days working in a laboratory that had an entire wall made of glass that allowed a view into the laboratory from the adjacent high traffic hallway. Like being in a fishbowl all day long.
We managed to 'turn the tables' by placing one of the magic eye posters on the glass, where we were able to entertain ourselves watching the weird gyrations people went through to discover the hidden 3D image. Most got it after a bit of study, while some never managed.
Somebody in the lab then acquired a magic eye poster that looked authentic but actually contained no image....which meant we were treated to an endless stream of employees working very hard using the standard approaches....squinted eyes, cross eyes, insane sideways looks meant to tease out an image that didn't exist. Many would show up several times a day, waiting impatiently for their time in front of the poster.
Often, out of frustration, they would enter the lab and propose what they thought they might be seeing...to which we always replied...."you're almost there!".