Hyperkinesia
A tic can be defined as a repeated, individually recognizable, intermittent movement or movement fragments that are almost always briefly suppressible and are usually associated with awareness of an urge to perform the movement. These abnormal movements occur with intervening periods of normal movement. These movements are predictable, often triggered by stress, excitement, suggestion, or brief voluntary suppressibility. Many children say that the onset of tics can stem from the strong urge to move. Tics can be either muscular (alter normal motor function) or vocal (alter normal speech) in nature and most commonly involve the face, mouth, eyes, head, neck or shoulder muscles. Tics can also be classified as simple motor tics (a single brief stereotyped movement or movement fragment), complex motor tics (a more complex or sequential movement involving multiple muscle
groups), or phonic tics (including simple, brief phonations or vocalizations).
List of motorcycles by type of engine
A transverse engine is an engine mounted in a vehicle so that the engine's crankshaft axis is perpendicular to the direction of travel. In a longitudinal engine configuration, the engine's crankshaft axis is parallel with the direction of travel. However, the description of the orientation of "V" and "flat" motorcycle engines differs from this convention. Motorcycles with a V-twin engine mounted with its crankshaft mounted in line with the frame, e.g. the Honda CX series, are said to have "transverse" engines, while motorcycles with a V-twin mounted with its crankshaft mounted perpendicular to the frame, e.g. most Harley-Davidsons, are said to have "longitudinal" engines. This convention uses the longest horizontal dimension (length or width) of the engine as its axis instead of the line of the crankshaft.