CIA technicians invented and used this unusual device in the 1960s to keep track of the enemy in Southeast Asia. The mission was to count people and supplies moving down the Ho Chi Minh Trail from North Vietnam to South Vietnam along the borders of Laos and Cambodia. Many of the Laotian trail watchers whom CIA recruited could not read or write, let alone understand English. And so the device featured “pictograms,” such as symbols representing troops, trucks, motorcycles, carts, bicycles, tanks, cannons, small artillery, missiles, donkeys, and yes, occasionally elephants, a common beast of burden in Laos. Alongside each pictogram was a knob that could be set to a number, and then the data could be transmitted to an airplane by activating a toggle switch.