In the previous book a translation was defined as an isometry that moves the points of the pre-image the same distance in one direction.  Translations can be vertical, horizontal, or oblique.  Oblique motion means the pre-image moves both horizontally and vertically to  reach its end location.  Below is an example of an oblique translation. ObliqueSlide

Notice that the orientation of the pre-image and image are the same, which means the order in which the pre-image points are listed follow the same order as their corresponding image points.  For example, starting at A on the pre-image and listing the points in a clockwise direction produces the list ABCD.  The points on the image have the same order if read in a clockwise direction, A′B′C′D′.