My CS teacher in high school had a lesson with us about horseshoe crab's eye, which apparently does not see anything that is larger than the field of view of the eye, allowing it to consume smaller organisms and omitting larger organisms. We used a neural network model in excel for such purposes.

He was (and hope he still is!) a great person, who taught me being curious and insightful in the computer science field. Taught me about Donald Knuth, TeX and many more things.