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 but unverified explanation for the QWERTY arrangement is that it was designed to reduce the likelihood of internal clashing of typebars by placing commonly used combinations of letters farther from each other inside the machine. Another story is that the QWERTY layout allowed early typewriter salesmen to impress their customers by being able to easily type out the example word "typewriter" without having learned the full keyboard layout , because "typewriter" can be spelled purely on the top row of the keyboard. However, there is no evidence to support these claims. A number of radically different layouts such as Dvorak