The Malling-Hansen writing ball is a proto-typewriter that, sadly for contemporary aesthetics, lost the battle for typewriting supremacy. This page from the Malling-Hansen Society claims it was superior to the winning design, and they may be correct; but it certainly is more striking (no pun intended) to my eye.
The whole apparatus (the writing ball included) is mounted on a stationary foundation plate in such a way that it can be moved down against a spring, when the writing ball or one of its pistons are forced down by the finger. The foundation plate has an upright anvil under the centre of the ball and directly under the paper frame. When a knob of a type piston is depressed, the paper resting on the anvil, below the same receives an impression. When the finger pressure on the type piston knob is removed, the instrument swings into its normal position. The escapement mechanism moved the paper frame that held the paper on space until the end of the line was reached. By pushing the button on the left in front of the ball all the way down, the carriage was turned concentrically back to the beginning of the line and moved one line to the left.The most famous of Rasmus Malling-Hansen's inventions: The Writing Ball (via Neatorama)
(Image: Auction Team Köln)