Music games are simulations of music performance in which players interact with music scores using a computer or mobile device. They may be played singly or in teams. Music games may be played by people of all ages, from children to adults. Most use a combination of keyboard and other controls to simulate an environment and facilitate interaction with the score. Music heardle game genres range from rhythm-based games such as "Punch Drunk Love" to more abstract scores such as "Soundself". In contrast to video game music, the music in these games is not composed specifically for the game; rather, it is composed according to the game's selectable parameters. Music for these games is often referred to as "instrumental backing tracks" or "music sheets", and can be adapted from existing songs, composed in-house or purchased from third party vendors. In some cases, new songs are composed specifically for the game. Other times, other non-game music is used as part of the overall aesthetic design. For example, theme songs may be used in lieu of an instrumental track. The arrangement can vary greatly between different games: while some employ simple high-tempo beats, others opt for more complex melodies and harmonies. Although most music games have been designed primarily for human players (with a few exceptions), some have also been designed to accommodate the input of digital pets such as virtual teddy