Math in motion: YouTuber turns plastic toy into functional computer

YouTuber Shadowman39 has created a fully functional 8-bit mechanical computer using K’NEX, the plastic construction toy typically used for building roller coasters and towers. This inventive machine features an arithmetic logic unit (ALU) made entirely from K’NEX rods, connectors, and gears, capable of performing basic arithmetic operations on numbers from 0 to 255 (or -128 to 127 in signed binary). The computer uses mechanical registers composed of levers to represent binary values, and a rack-and-pinion drive system powers the calculation process. Unlike electronic computers, this mechanical model visibly demonstrates each step of the computation, making the operation transparent and educational. Building a precise mechanical computer from flexible plastic pieces posed significant engineering challenges, as K’NEX components are not designed for high-precision tasks and can loosen over time. Shadowman39 overcame these difficulties by carefully designing networks of levers and gears to replicate binary addition logic gates, reminiscent of 19th-century mechanical calculators