My pleasure, I’m always down for nerding out on stuff like this.

Another fun example of the early visual processing is feature detection. The parallel processing allows us to instantly find a green square in a sea of red squares, as it jumps out at you.

But when you combine multiple independent features together (find the green square in a sea of red and green squares and circles) now we have to tediously look around the whole image. That integration of multiple features forces the work higher up in the visual system and takes more time, attention, and effort. Thats why Where’s Waldo is hard.

https://i.imgur.com/2UZhT3I.jpeg