French mathematician, physicist, and philosopher Blaise Pascal was an all-around intellectual bad-ass. In his rather short life — Pascal succumbed to stomach cancer at the age of 39 — he managed to write dozens of mathematical treatises that paved the way for projective geometry and probability theory, was a pioneer of hydraulic sciences, and is even credited with wearing the first wristwatch.

At 16, Pascal wrote a mathematical proof regarding conic sections called the Hexagrammum Mysticum Theorem, still known today as Pascal’s theorem. The theory was so groundbreaking at the time, fellow intellectual heavyweight René Descartes accused Pascal’s father of writing the theory and putting the younger Pascal’s name on it to create false notoriety for the boy. And though his contemporaries verified the work indeed belonged to Pascal the Younger, it created what amounted to two decades of 17th century France’s equivalent to a Twitter beef between the two influential thinkers.

As it turns out, sensational mathematical treatises were great for name recognition, but not so lucrative financially. Though proving the esteemed Descartes wrong cemented Pascal as a child prodigy, he was already being recruited into the rather mundane family business of tax collecting. However, young Blaise wasn’t just a mathematical genius, he was also a fairly savvy marketer: After watching Papa Pascal’s daily struggles of manually calculating tax debts and payments with nothing but an abacus, pen, and paper, the enterprising youth decided to throw his talents into a commercial venture: the manufacturing of a mechanical calculator.

Almost 300 years before the first solid state electronic calculator was produced, Pascal set out to create a calculating machine that could automate the process of basic mathematical functions. Using the latest technology at his disposal — namely gears, springs, and gravity — 19-year-old Pascal debuted his Pascaline machine. The premise was fairly simple. For addition, you simply inserted a stylus into a gear to choose the intended digit. Once all the digits were entered, the gears “stored” the first number, while the process was repeated for the second number. Once complete, the sum appeared in the windows at the top of the device.

For being based on such rudimentary technology, Pascal’s number-cruncher packed in a lot of innovation. For subtraction problems, Pascal included a second set of windows (accessed by a sliding panel) with gears pre-programmed to use nines-compliment arithmetic. While explaining compliment arithmetic is well above my pay grade (the video above gives a great walk-through), similar variations of compliment arithmetic are still used to handle integers by computer programmers today.

His carry-over system (carrying the values from 10s to 100s to 1000s, etc.) became so sophisticated that later versions of the machine were eventually able to process values up to eight digits long. With the proper configuring, the machine was even able to handle multiplication and division problems using repetition in the same method used by mechanical calculators through the 20th century. In fact, his creation of a gear system able to convert numbers across decimal places can still be found in analog odometers, gas pumps, and electricity meters.

Perhaps one of the most overlooked innovations of the Pascaline was its size: even the original version of the machine was portable. Considering early electronic computers designed to compute basic equations often took up several large rooms, to think that Pascal was able to craft an adding machine no bigger than a breadbox almost 300 years before the first microprocessor was invented, is straight-up mind-blowing.

Unfortunately for Pascal, even after being granted exclusive rights to design and manufacture calculating machines by King Louis XIV of France, the Pascaline was a flop. Not only was the learning curve to operate the machine steep, but 17th century accountants feared that this type of automation would eventually put them out of a job. The machine was incredibly expensive to produce; well before the invention of the assembly line, Pascal himself had to build each machine by hand.

And as it turns out, French currency did Pascal no favors. The French stopped minting the franc and moved to much more complicated system based on the silver écu and gold Louis d’or that converted in wacky ways for which the Pascaline simply could not account.

Thankfully, Pascal’s failure to become the Steve Jobs of his era was a bit of a blessing for the rest of the world. Instead of dedicating his life to peddling portable calculating machines to the masses, Pascal went on to produce a diverse body of academic work that would influence mathematicians, economists, philosophers, and computer programmers alike for the next five centuries. Thus his contributions to science became, yes, incalculable.