On a summer afternoon in 1894, William Barkalow had a drink or three and got on his horse. He rode it down the central sidewalk of Long Branch, New Jersey, where horses were, even in those primordial days of traffic regulation, definitely not supposed to go.
Barkalow rode amongst the foot traffic like an electric scooter before its time.
The next day's New York Times reported that he paid no heed to a police officer's shouts, nor the billy club flung at him. And while Barkalow didn't trample anyone, his breach of footpath etiquette proved so intolerable that the officer finally shot him between the shoulder blades.
The turn of the century was a rough time in the history of the footpath.
Ubiquitous strips of not-street were squeezed thinner and thinner to make way for horses, trolleys and eventually lanes of vehicles.
The footed masses fought with vendors and construction crews for the leftover pavement as if it were some Mesopotamian riverbed.
"The pedestrians now, as formerly, must spend their time in a hurdle race over skids, climb platforms, dodge moving boxes or else run the risk of being crushed under horses' hoofs in the street," the Times complained in 1896, as part of its newly launched "crusade against the sidewalk grabbers".
There's a new kind of footpath grabber today - more agile than Barkalow's horse, popping seemingly from nowhere into the paths of pedestrians at 16-30km/h.
Thousands of rentable electric scooters have taken over pavement from Washington, DC, to Santa Monica and Austin to Chicago.
They clog narrow footpath, startle us from our ambulatory texting sessions, and lay strewn in the middle of crosswalks. It's hard to recall a time in living memory when it's been more nerve-wracking to attempt a stroll.
The physical injuries are one thing: A 75-year-old man tripped over an abandoned scooter in San Diego and shattered his knee. A 7-year-old boy near Los Angeles reportedly had his teeth knocked out by a scooter rider. A 44-year-old woman was hit by a Bird in a Cincinnati intersection. The assailant had their Bird account suspended, while the woman got a US$1000 medical bill. And on the other side of the gutter, car-on-scooter fatalities are becoming almost commonplace.
But for every broken tooth there are countless jostled states of mind, as pedestrians discover the placid streams by which they travel have been invaded en masse by machines with names like Bird and Jump and Spin and Skip.
Jacob Hege, 22, has walked to work a bit more cautiously since last Tuesday morning, when he emerged from a crosswalk on 16th Street NW in Washington and felt something thwack him from behind.
He turned to see a woman on a Bird scooter, which like several other brands in the District of Columbia can be found on almost any block and rented for a few dollars.
"We both got knocked to the side," Hege said.
"She had AirPods in, and she looked at me with such anger and said, 'Move!' and scooted away. And I stood looking at her like, what?"
Once again, there's a people's crusade to restore the sanctity of the footpath, with anti-scooter vigilantes appearing wherever the machines do.
Scooters are piled into dumpsters, chucked into rivers, thrown through windshields, set on fire and hung from bridge posts like apparatchiks of a deposed regime.
In Hoboken, New Jersey - the state's first major beachhead for scooters - an anonymous Twitter documentarian records rider buzzing strollers and smashing into each other.
In Atlanta, a man in a wheelchair who calls himself John Plantaseed has taken to knocking down rows of scooters like chains of dominoes, yelling triumphant obscenities as they clatter to the pavement.
Cities are trying to mitigate the backlash. Washington will begin experimenting with solar powered charging docks, hoping to break riders' habit of dumping the scooters wherever they happen to get off.
But sometimes no balance can be found.
Nashville's mayor is now seeking to evict all scooters from the streets.
We could use some perspective, because this is not the first sidewalk war by any means.
The first known footpath were laid in central Anatolia around 2000BC - a millennium or two after the invention of the wheel, according to the book "Sidewalks: Conflict and Negotiation over Public Space."
They remained rare luxuries in most of the world until the 19th century, when the big cities like London and Paris built hundreds of miles of the stuff.
But it took decades of social conditioning before "walk" became the operative syllable in sidewalk. For most of human history, vehicles, pedestrians, vendors, musicians, drinkers and strolling lovers all mingled in the same amorphous muck of the avenue. It's only in the past century or so that those corridors have been divided up, stratified, painted with lines regulated in the name of more efficient movement.
Jaywalkers - a word that did not exist until the early 20th century - were shamed and fined for straying into the street. Non-walkers were similarly penalised from clogging up the precious footpaths.
"City after city started issuing ordinances prohibiting or regulating a number of sidewalk activities from street vending to political and commercial speech, from the display of wares on the sidewalk to loitering, panhandling, and prostitution," reads the book.
Detroit went so far as to paint "huge yellow footsteps" on its footpaths in the 1920s, lest any ped fail to get the message.
This social order worked fine, except when it didn't.
Bicycles, newspaper boxes, mass homelessness, plodding iPhone gazers - all these things disturbed the fiction of a street neatly divided into walkers and cars. Cities simply invented new regulations and lanes to restore the peace, which worked until the next disruption came along, and here we are today in scooter hell.
But is it a hell made by scooters, or just made apparent by them?
"I see this conflict more as an outcome of bad decisions and bad design," said Anastasia Loukaitou-Sideris, co-author of Sidewalks and an urban planning professor at the scooter-saturated campus of UCLA.
"Cities kept widening the streets and narrowing the sidewalks, and downgrading activities to accommodate only walking ... I don't mean to say sometimes scooter drivers are not obnoxious. But I'd say it's a less obnoxious use than cars."
Loukaitou-Sideris expects the cities will find a way out of this jam, whether by restricting scooters or squeezing yet more lanes into the finite space between buildings.
Footpath disputes always resolve one way or the other. Just ask William Barkalow.