There’s a strange little pilgrimage site in San Francisco, and hardly anyone knows about it. A plaque near 406 Market Street marks where a German immigrant mechanic named Charles Fey built, sometime around 1895, a cast-iron box with three spinning reels and five symbols: horseshoes, diamonds, spades, hearts and a cracked Liberty Bell. Line up three bells and the machine paid out fifty cents — ten nickels, clattering into a tin cup.
He called it the Liberty Bell, and he had no idea he’d just invented one of the most successful entertainment machines in human history.
I find this origin story genuinely fascinating, partly because the machine in your pocket today — the one a Kiwi might open on the bus in Wellington — still carries Fey’s DNA. Three reels became five, nickels became pixels, but the fundamental promise is identical: pull, wait, find out. What changed completely is what’s happening inside. And that’s the part most people get wrong.
The mechanical era, briefly and lovingly
Fey’s genius wasn’t the spinning reels — poker machines with cards on drums already existed in 1890s saloons. His breakthrough was the automatic payout. Earlier machines needed a bartender to hand over your cigar or drink; the Liberty Bell paid by itself, which meant it could stand anywhere, unattended, earning. That one engineering decision created an industry.
A few waypoints from there:
- 1902–1908 — gambling machine bans spread across the US, so manufacturers pivoted to “trade stimulators” paying out fruit-flavoured gum. That’s why slots the world over still show cherries, lemons and plums, and why the BAR symbol is widely traced to the Bell-Fruit Gum company logo. Your modern pokie is wearing a century-old legal disguise.
- 1963 — Bally’s Money Honey, the first fully electromechanical slot, with a hopper that could pay 500 coins. The lever became decorative.
- 1976 — the first true video slot, built in Las Vegas on a modified 19-inch Sony TV screen.
- 1996 — “second screen” bonus rounds arrive, and slots stop being purely about the reels.
- Late 1990s onward — the internet, and the whole machine dissolves into software.
There’s something almost poetic about that arc: a hundred years to perfect a physical object, then twenty to make the object disappear entirely.
So what’s actually inside a modern slot?
Here’s the bit worth slowing down for, because nearly every myth about slots dies once you understand one component: the random number generator.
A modern slot — physical or online — has no spinning anything. The RNG is a program generating thousands of number combinations every second, continuously, whether anyone’s playing or not. The instant you press spin, the current number is grabbed, and that number already determines the outcome. The reels you then watch? Animation. Theatre. The result existed before the first symbol moved.
Once that clicks, the folklore collapses on its own. The machine isn’t “due” after a losing streak — each spin is independent, the RNG has no memory. It doesn’t run “hot” at certain hours. Someone winning on “your” machine two minutes after you left didn’t take your jackpot; they pressed the button at a different millisecond, which is the entire difference.
Mathematician Joseph Bertrand wrote, back in 1889, the line that casino mathematicians still quote:
“How dare we speak of the laws of chance? Is not chance the antithesis of all law?”
And yet it isn’t — that’s the elegant trick. Individual spins are pure chance; millions of spins obey precise statistics. Which brings us to the two numbers that define every slot ever made.
RTP — return to player. A slot with 96% RTP returns, across millions of spins, $96 of every $100 wagered. Not to you personally, and not tonight — across the whole lifetime of the game, to everyone combined. The remaining 4% is the house edge, and it’s how the lights stay on.
Volatility. Two slots can share 96% RTP and feel like different sports. Low volatility pays small and often; high volatility pays rarely and big. Neither is “better” — one suits a long relaxed session, the other suits people who enjoy droughts and spikes. Knowing your temperament here matters more than any strategy anyone will ever try to sell you. (And they will try. None of them work. The RNG cannot hear your strategy.)
From pub corner to browser tab
For New Zealanders the physical version of this story is the pokie — about 14,000 of them sit in pubs and clubs across the country under Gambling Act 2003 class 4 licensing, plus the casino floors in Auckland, Christchurch, Dunedin and Queenstown. The online chapter happened offshore: NZ law doesn’t prohibit Kiwis from playing on overseas-based sites, which is where the modern catalogue lives, and a new licensing regime arriving from 2026 is set to bring that market under local regulation for the first time.
And the catalogue really is the striking part. Where Fey offered one machine, today the online slot games available to NZ players number in the thousands on a single platform — LevelUp’s lobby alone spans everything from deliberately retro three-reelers (Fey would recognise them instantly) to Megaways titles with 117,649 ways to win. The honest advantage of the online format, beyond sheer variety, is transparency: each game publishes its RTP and volatility in the info panel, something no mechanical machine ever disclosed. The honest disadvantage is speed — online spins resolve faster than physical reels ever did, so a budget disappears faster too. Same maths, higher tempo.
Which is why the sensible ritual before playing anywhere, LevelUp included, is thirty seconds in two places: the game’s info screen (RTP, volatility) and the account’s limit settings (deposit cap, session reminder). Fey’s customers were limited by the nickels in their pocket; we have to build the pocket ourselves.
What Fey’s bell still teaches
A century and a quarter later, the design brief hasn’t changed: a machine that converts uncertainty into entertainment, a few cents at a time. The engineering went from cast iron to cryptographic RNGs, the fruit symbols outlived the gum they once advertised, and the tin cup of nickels became a number on a screen.
But the honest way to enjoy the thing is the same as it was at 406 Market Street. It’s a show with a ticket price. The maths guarantees the house a few percent over the long run — that’s not a scandal, it’s the product working as designed, same as a cinema charging for a film.
Fey died in 1944, reportedly still tinkering. I like to think he’d be less amazed by the technology than by the scale — and quietly pleased that, after all the reinvention, we still line up three of a kind and feel that same small, ancient thrill.
