A twizzle differs from a figure skating spin in that it travels across the ice instead of being centered in one spot. Usually skaters turn for at least four revolutions on a twizzle. 
Twizzles can be performed both forward and backward, on both inside and outside edges, and both clockwise and counterclockwise. Twizzles are most commonly performed in an upright position with the free foot held close to the skating leg, but other variants are possible as well, such as a twizzle in a sit spin position.
Speed, ice coverage i.e. distance, unison (couples), closeness (couples), variety and difficulty of positions, change of rotational direction (counter-clockwise, clockwise), and difficult entries are taken into consideration by the judges and technical specialists.