to prevent falls by the horse. Types of jumps used include the following: Vertical (or upright) – a jump that consists of poles or planks placed one directly above another with no spread, or width, to jump Oxer – two verticals close together, to make the jump wider, also called a spread Square oxer (sometimes known as Box Oxer): both top poles are of an equal height Ascending oxer (usually called a Ramped Oxer): the furthest pole is higher than the first Descending oxer (usually called an Offset Oxer): the furthest pole is lower than the closest. Descending oxers are not used in competitions and competitors are forbidden from jumping it. This is due to the fact that the horse may not be able to see the furthest pole before making the jump. Swedish oxer: the poles slant in opposite directions, so that they appear to form an "X" shape when seen head on Triple bar – is a spread fence using three elements of graduating heights Cross rail – not commonly used in sanctioned horse shows, and sometimes called a "cross-pole," two poles crossed with one end of each pole being on the ground and on jump standards so that the center is lower than the sides; used at small shows and for schooling purposes to help teach the rider how to properly aim the horse jump in the center of the fence Wall – This type of jump is usually made to resemble a brick wall, but the "bricks" are constructed of a lightweight material and fall easily when knocked. Hogsback – a type of spread fence with three rails where the tallest pole is in the center Filler – this is not a type of fence, but is a solid part below the poles, such as flower boxes or a rolltop; it also may be a gate or other filling decorative pieces Combination – usually two or three jumps in a row, with no more than two strides between each; two jumps in a row are called double combinations, and three jumps in a row are called triple combinations (if a horse refuses the second or third element in one of these combinations, they must jump the whole combination again, not just any obstacle missed) Fan: the rails on one side of the fence are spread out by standards, making the fence take the shape of a