Typeball

When IBM launched the Selectric in 1961 it dropped typebars and the moving carriage entirely. Every character sat on a single ball that tilted and rotated to strike the right glyph against the paper, while the paper stayed put and the ball travelled sideways. It earned an affectionate nickname: everyone called it the "golf ball". Swapping the ball gave a new typeface or a different alphabet in seconds — a revolution against fixed typebars. The same element drove terminals and printers such as the IBM 2741. The daisy wheel and NEC's tulip-shaped thimble were later takes on the same idea: change the element, change the font.