Mechanical pianos are self-playing instruments that use a system of mechanical components to produce music. They often feature a series of pinned cylinders or discs that trigger hammers to strike the strings, creating sound. These pianos can play pre-programmed tunes without the need for a human pianist. One popular type of mechanical piano is the player piano, which allows users to insert rolls of paper or digital media to play music automatically. Mechanical pianos have a rich history, dating back to the 18th century, and they continue to be appreciated for their unique charm and nostalgic appeal.