I’ve used this technique since I was a kid, and have always been fascinated with how my eyes perceive both a 3d image and simultaneously two separate images ove

I’ve used this technique since I was a kid, and have always been fascinated with how my eyes perceive both a 3d image and simultaneously two separate images overlaid. It’s something I think about many times per day - I mean, I’m looking at stuff all day, and this is such a fundamental aspect of the experience of looking at something. But my impression is that most people are only barely aware of how this works?