In studio settings, actors may work on soundstages, which are large indoor spaces designed to mimic real-world environments. They may also work in front of green screens, which allow special effects to be added later in post-production. Actors portray characters in stories such as plays, musicals, films, television shows and radio shows. They engage with the audience and convince them through altered speech patterns, hand gestures and more that they truly are the character. When necessary, actors also change their appearance such as their hair color or body weight to physically portray and embody their character.