The story of Pong has been told many times, and of course it makes for a more compelling story if the game's precursors aren't mentioned. Bushnell and Alcorn, much like Jobs and Wozniak (the two Steves who founded Apple), are cultural heroes who are too often portrayed as mad scientist-types, geniuses who woke up one morning, shouted "Eureka!" and went about creating the world's first video games and personal computers, respectively.

As we've seen already, however, Pong was not even the first coin-operated video game, much less the first video game. It wasn't even the first video game based on "pinging" a ball back and forth across a screen, not by a long shot. To begin then, we must recap the events that led up to that fateful day in November 1972.

The origins of today's computing power can be traced to World War II. The U.S. Army was on a continuous quest to gain the upper hand against the Axis Powers, and several promising projects -- and some not-so-promising -- were given funding on the chance that a few might be successful. One such proposal was to create a high-speed electronic device to calculate ballistics firing tables, which at the time was being performed manually by female mathematicians called "computers."

Development of the Electronic Numerical Integrator and Computer -- better known as ENIAC -- began in 1943; however, it did not become fully operational until 1946, when it became the first comprehensive reprogrammable digital computer.

Conceived and designed by John Mauchly and John Eckert, the room-sized ENIAC influenced the development of later increasingly smaller and more powerful computers from a variety of commercial companies, beginning the slow transition from centuries-old mechanical and analog paradigms to fully digital devices.

Unreliable and bulky vacuum tubes used into the 1950s were phased out in the 1960s by transistors that were more reliable, yet less expensive. These transistors were soon incorporated into the Integrated Circuit, or IC, where a large number of these semiconductor devices were placed onto small silicon chips.

Nevertheless, after several decades of innovation in circuitry and refinements in operation and utility -- including a switch to a stored-program methodology that offered a fully reprogrammable environment -- large and expensive mainframe computers still remained the norm.

A modern simulation of OXO running on the EDSAC mainframe.

Despite the size and cost restrictions that limited these computing systems to government and large institutions such as universities, games found their way onto even the earliest mainframes, starting the ongoing trend of implementing video games wherever a viable platform presented itself.

The first known instance of an actual implementation was Alexander Douglas's 1952 creation of OXO (also known as Naughts and Crosses), a simple graphical single-player-versus-the-computer tic-tac-toe game on the EDSAC mainframe at the University of Cambridge. Although more proof of a concept than a compelling gameplay experience, OXO nevertheless set the precedent of using a computer to play games.

A simulated screenshot of what Tennis for Two looked like.

The first known precursor of Pong debuted in 1958 on a visitors' day at the Brookhaven National Laboratory in Upton, New York. It was there that William Higinbotham and Robert Dvorak demonstrated Tennis for Two, a small analog computer game that used an oscilloscope for its display.

Tennis for Two rendered a moving ball that was affected by gravity (the first known use of physics[1] in a game) in a simplified side view of a tennis court. Each player could rotate a knob to change the angle of the ball, and the press of a button sent the ball toward the opposite side of the court.

As with OXO, few people got to experience Tennis for Two, but in many ways it can be considered the first dedicated video game system. Without the benefit of hindsight, this milestone was even lost on the game's creators, who, after a second visitors' day one year later, disassembled the machine's components for use in other projects.

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[1] Defined as the science of matter and energy and their interactions, with a focus on the latter when it comes to videogames.