When a rainbow appeared in the sky over Tugu, a neighborhood in Jakarta, Robert Blust did what came naturally: he pointed to it. The year was 1980, and Blust, then a professor at the University of Leiden in the Netherlands, was waiting for lunch with a group of teachers from around Indonesia. One of the teachers, seeing Blust’s gesture, politely informed him that, in Sumatra, pointing to rainbows was considered a no-no. Another chimed in to say the same was true where he came from, in a different part of…
