Before uniting behind a single symbol, scientists working with dangerous biological materials faced a dizzying array of warning labels that varied from one laboratory to the next. Then, in 1966, Charles L. Baldwin of Dow Chemical and Robert S. Runkle of the National Institutes of Health co-published a critical paper in Science. Their piece called for the adoption of the biological hazard (or: biohazard) symbol as we know it today. This new symbol they hoped to become standard, however, was unconventional: a crowd-tested solution designed to be maximally devoid of obvious meaning or associations.

Costa Rica uses an idiosyncratic system of addresses that relies on landmarks, history and quite a bit of guesswork. My apartment, for instance, is three houses down from the local high school. The high school’s official address is 300 meters east of the elementary school. The elementary school’s address is across the street from the church — or next to the bar, depending on your piety.