A movement is a self-contained part of a musical work. While individual or selected movements from a composition are sometimes performed separately, a performance of the complete work requires all the movements to be performed in succession. Often a composer attempts to interrelate the movements thematically, or sometimes in more subtle ways, in order that the individual movements exert a cumulative effect. In some forms, composers sometimes link the movements, or ask for them to be played without a pause between them.