 Digital pianos, such as those offered by Roland, provide interactive lessons and games using the built-in features of the instrument to teach music fundamentals.Development of digital musical technologies can be traced back to the analog music technologies of the early 20th century, such as the electromechanical Hammond organ, which was invented in 1929.In the 2010s, the ontological range of music technology has greatly increased, and it may now be electronic, digital, software-based or indeed even purely conceptual.