There are two primary forms&colon; rigid frame and articulating frame. Lock added that complications were beyond Pete's grasp and that he had trouble articulating emotions. Arneson Surface Drive-16 articulating propulsion systems drives provide the vessel with thrust vectoring control. Their transverse processes (processes articulating with the ribs) slightly increased in length towards the back. The Enhanced M4 uses an articulating link piston operating system. Similarly, dysarthria, another motor speech disorder, is characterized by difficulty articulating sounds. It is the first camera which has an articulating LCD screen. Babbling allows the infant to experiment with articulating sounds without having to attend to meaning. Juan de la Cierva developed the fully articulating rotor for the autogyro. The passenger doors are articulating "falcon-wing" designs that open vertically. Poster advertising, proposing a travel destination, or simply artistically articulating a place have been made. Articulating headrests are no longer available.