[Netizen Cuckoo: In junior high school, when the teacher was teaching about convex lenses, I went and asked the teacher if we could cut out the middle part, keep only the curved surfaces, and make it thin. Later I found out this thing actually works; it's called a Fresnel lens!]
[Netizen Reply: Genius! If you had been born a few centuries earlier, this lens would be called the Cuckoo lens!]
[Another netizen replying to the previous one: Born a few centuries earlier, he might not even have had a chance to go to school!]
Chapter 45