Instead of electrical signals, mechanical computers utilize complex systems of gears, weights, and other physical implements to perform tasks. Mechanical computers may not oversee today’s automated tasks, but it’s still possible to build your own using literal children’s toys. Although he’s planning on expanding its abilities, the YouTuber recently uploaded the first look at his Knex 8-bit mechanical computer—specifically its “very simple” arithmetic logic unit, or ALU. “Very simple,” in this case, refers to a roughly 3.5-foot-tall contraption built using thousands of Knex pieces, wheels, and conveyor belts. It may not find its way onto desktops, but the Knex project highlights the uniquely tactile and ingenious designs required to construct even the most rudimentary of mechanical computers.