Drop a quarter—or four—in the coin door, and a pinball machine will whir to life. Boom: lights flash, the scoreboard resets, and a stainless-steel ball clinks into place, ready to hurtle down the shooter alley toward a maze of ramps, bumpers, and traps.
Casual players tend to experience pinball as a frenzied series of events that inevitably culminate in a ball breezing past a set of flippers, down a drain, and back to its home beneath the glowing playfield. Without an expert touch, the game can feel almost happenstance, the ball zigging and zagging at the mercy of small movements from flippers and sinking and rising surfaces. In reality, though, pinball is anything but random. You just have to open a machine to learn its secrets.
Every pinball machine is a mini marvel of engineering. Its guts are a complex series of interconnected machines designed with Rube-Goldbergian precision. “We like to describe it as a world under glass,” says Eric Meunier, a game designer at New Jersey-based Jersey Jack Pinball, one of the last remaining pinball manufacturers in the United States.
Pinball has changed drastically over the years, from running exclusively on solenoids and relays—coils of wire that, when energized with electricity, make pinball mechanics move—to relying primarily on microprocessors and circuit boards. Even still, every old or new game starts more or less the same way. “The first three inches of a game are always the same,” Meunier says. “But after that, the ball could go anywhere.”
After the player pulls the spring-loaded plunger, the ball will travel through the shooter alley and enter a mini amusement park of obstacles that impact its path through the game. Modern pinball machines are built from thousands of parts, if you count things like screws and washers, and most come loaded with a few well-known components. These include flippers, the small mechanical wings players activate by pressing a button on the side of the game’s cabinet; pop bumpers, the mushroom-shaped targets that send the ball flying when touched; ramps, to direct the ball to a new area of the playfield; magnets hidden below the playfield to stop the ball or divert its path; a logic board to process the ball’s position on the playfield and keep track of game play and score; a drain, the hole at the bottom of the playfield where the ball goes when you lose; and a tilt bob, a mechanical sensor under the machine that can sense when a player is tilting the machine too far. It’s up to the designer to lay out the components in imaginative ways and create new toys and tricks that can entice collectors and arcade owners to buy a machine.
For designers like Meunier, a pinball game is a puzzle; each component, whether a ramp or a wire, must be in place for the full picture to come into focus. Designers are often trained as electrical or mechanical engineers, and they approach pinball with a scientific eye. They can spend years mocking up playfields and confabing with the art department before a game ever gets built. “It’s a symbiosis,” Meunier says of the process. “The art has to tie into the rules, and the rules have to tie into the shots.”
Most designers start crafting a game with a narrative in mind, which is usually dictated by a film or TV show. From there, they build the playfield’s shots and components around that storyline. Early versions of a game are designed on something called a whiteboard: a piece of slanted wood acts as a physical blueprint, allowing designers to lay out a complex series of components that ensure a game plays as planned. “The way I design a game is to have a lot of broad features that a non-pinball-player—we call them ‘casuals’—can see and easily achieve when they walk up to the game,” Meunier explains.
The average game is designed to last three minutes, a length of time established back when bars and arcades had to turn a profit off the machines. (Today, most of Jersey Jack’s machines are privately owned.) Designers can tweak the layout of a playfield to be more or less challenging by doing things like widening an outlane (the lanes at the far side of the playfield that lead to the drain), or adding a bumper closer to the drain. And game owners can fine-tune software to determine the power behind an electrical jolt to the flipper, which can also impact game play.
Things such as ramps, lanes, spinners, and blinking lights are meant to provide visual targets, and are not particularly complicated in and of themselves: pull the spring-loaded plunger and the ball goes flying. Press a button and the flippers flick. Shoot the ball up a ramp and it’ll roll back down. But when arranged inside a pinball machine’s cabinet, the components create a deliberate maze of cause and effect, all set up to challenge the player and—ideally—make the arcade money.
Pinball wasn’t always so aggressively engineered, and early machines relied on chance. In the 18th century, French aristocrats played a game called bagatelle, an indoor version of croquet in which a player would use a cue to shoot a ball across a wooden table and attempt to sink it into various holes. In the late 1800s, bagatelle evolved into a proto-Plinko setup, in which players would use a spring-loaded plunger to send a metal ball up a sloped playfield, where it would score points as it clinked past a field of pins.
Pinball’s predecessors required little skill, which explains why the game was considered a form of illegal gambling in most U.S. states until 1947, when the pinball manufacturer Gottlieb introduced the arcade game Humpty Dumpty. Gottlieb’s game was the first to use flippers; this new tool gave players more control over where to shoot the ball, which eventually led to its legalization as state courts decided that pinball was a game of skill, not chance.
You can still find pinball machines lighting up casinos today. But modern pinball is anchored by rationale, says Mark Gibson, whose traveling exhibition, Fun With Pinball, explains the science behind pinball components such as flippers, bumpers, and solenoids. “Pinball machines are programmed with a set of rules that behave very predictably,” he says. “What makes it seem arbitrary is the motion of the ball.”
From the 1940s to ’70s, pinball machines functioned like mechanical computers, relying on a complex series of physical components such as relays and switches to activate every part of the machine. “It was basically just a bunch of switches that got actuated and went from step to step to step,” says Michael Schiess, director of the Pacific Pinball Museum in Alameda, California, whose Visible Pinball Machine puts the game’s insides on display.
Lift the colorful ramp on one of Schiess’s transparent games, and you’ll see an organized mess of solenoids, wires, and motors that work together to tell the machine when to activate a flipper or add 500 points to your score. Lift the ramp on one of Meunier’s games, and you get a vastly different view: at Jersey Jack, Meunier designs “solid-state games,” named for the interior logic board that handles all the computing involved in modern pinball machines.
Instead of relying on individual mechanical parts to tell the scoreboard when to register a point or when a chime should sound, solid-state games have abstracted all of that away, with circuit boards that can track the ball’s location on the playfield, keep score, activate lights and sounds, and power general game play. “We’re essentially building big PCs,” he says.
Though the computer is the brains of a modern pinball machine, a player’s path through the playfield ultimately depends on skill. Every ball is equal when it kicks up to the shooter lane, but finesse (or, more likely, lack thereof) determines where the ball rolls. It’s that tension—between engineering precision and the unpredictable reality of physics—that keeps players plugging the coin door time and time again. “That’s the nature of pinball,” says Schiess. “And that’s why it’s survived for so long.”