As the pandemic continues, these improvised social-distancing symbols are slowly starting to evolve into more standardised markers – a kind of evolution that has precedent. For instance, before most cities eventually adopted the zebra crossing, each town marked pedestrian crossings in different ways. Britain mostly used metal studs and poles on the side, while Detroit used tennis-court lines. Eventually, the 1949 Geneva Convention on Road Traffic established uniform traffic rules across countries and most cities adopted the now iconic zebra crossing sign.