Old typewriters had different keyboard layouts. Some typewriters had a full keyboard with separate keys for each character, while others had three banks of keys and two shifts: one for capital letters and one for numbers and symbols. One early typewriter used a keyboard that resembled a piano and had 28 keys arranged alphabetically. This was the most efficient arrangement because users would know immediately where to find each letter. The QWERTY keyboard layout was created for the Sholes and Glidden typewriter and sold to E. Remington and Sons in 1873. ^{interestingengineering.com 2 1 3}