Uhm. "Google colors" are the three primary colors plus green. Or, if you prefer, the three primary colors plus yellow. Light vs. pigment. Do you have any idea how many things in the universe use that set of four colors? Walk down the toddler aisle of any toy store, for starters. Check out the plastic-coated wire at your hardware store.
Oh, wait. There are four colors of pipes. The text explains red and blue. What's in the other two colors? Are they non-functional pipes, sneaked in so you can't tell which ones are real? Disguised wiring? Message tubes? Is it deliberate obfuscation, where in reality green is hot water and red is cold? What's yellow-- sewage?
...and the green pipes discharge sites which may provide an answer to the searcher's query in such a manner that the searcher may not have to click on an ad. Fig. 12-4 L. Page, et al.; "The PageRank Public Company Ranking: Squeezing Cash out of the Web"; Stanford Digital Libraries Working Paper; XP002951571; pp. 1-17; Jul. 2013. cited by applicant.