I remember reading a sci fi novel a long time ago where mankind encountered a spider-like intelligent lifeform with an unusual method of communication. Wrapped around the creature's head is some type of organ which displays changing bands of light forming a kind of language. Instead of telling someone something they can show them instead.
I wish I knew the book and author. I feel like it could have been in either Clarke's Rama series or Varley's Gaea trilogy.
Rama definitely had octospider robot creatures that communicated with patterns of light on their skin, kind of like cephalopods iirc, but the 90’s were a while ago and I can’t remember many details. Wasn’t Dr. Blue a spiderbot with a ‘speech impediment’ where he could only display blue, or something like that?
Reminds me of the cuttlefish robot that was able to go back and forth tricking a real one into treating it like a male and female by changing its color patterns.
I was just listening to this podcast and the woman being interviewed, Sylvia Earle, said that according to Edith Widder, a bioluminescence specialists, light signals are the most common type of communication on the planet due to all the animals using it in the ocean. I would have never guessed that.