Square grand pianos, also known as square pianos, square grands, or box pianos, were a popular type of piano in the 18th and 19th centuries. These pianos are characterized by their rectangular or square-shaped cases. The shorter string length and action design can result in a less powerful and less sustained sound compared to grand pianos with more advanced actions. It's important to note that square grand pianos are no longer manufactured, and many surviving examples are considered antique instruments. While their tonal characteristics might differ from modern pianos, they hold a unique place in the history of piano design and are prized by collectors and enthusiasts for their historical and aesthetic value.