Escalator stairs with brushLife is full of little mysteries – for instance, why do some new-build homes have bricked-up windows, and what does the mysterious cable airline staff sometimes holds in front of a grounded plane really do? Then, there are the more frustrating questions, like why chocolate is so expensive right now and why you can’t stop watching that terrible TV show. A recent scroll on Reddit brought me to an everyday conundrum I’d never stopped to think about, too.Writing to r/whatisthisthing, site member u/kristhecadet asked: “What is this thing that you always see on an escalator?”.