Sholes and Glidden typewriter length. The redesigned platen also introduced the modern spacing functionality (horizontal and axial movement providing letter and line spacing, respectively). The cylindrical platen became "an indispensable part of every standard [typewriter]". By the end of 1872, the appearance and function of the typewriter had assumed the form that would become standard in the industry and remain largely unchanged for the next century. Although the machine possessed a cylindrical platen and what was essentially a QWERTY keyboard, two design elements that would later become essential were lacking: the ability to write in upper and lowercase letters and "visible" print. Although the
Typewriter one to superimpose multiple keystrikes on a single location. The ¢ symbol (meaning cents) was located above the number 6 on electric typewriters, while ASCII computer keyboards have ^ instead. A number of typographical conventions originate from the widespread use of the typewriter, based on the characteristics and limitations of the typewriter itself. For example, the QWERTY keyboard typewriter did not include keys for the en dash and the em dash. To overcome this limitation, users typically typed more than one adjacent hyphen to approximate these symbols. This typewriter convention is still sometimes used today, even though modern computer word