A transformation is a function that changes a figure in a particular way — it can change the position, size, or orientation of a figure. The original figure is called the preimage and the figure produced is called the image of the transformation. A prime symbol is often added to the label of a transformed point to denote that it is an image. Transformations are sometimes expressed as a mapping because they map the inputs to the outputs. Note that an input can be a single point. Here, $T$ is the transformation, $x$ and $y$ are the coordinates of the point of the preimage, and $x^{\prime }$ and $y^{\prime }$ are the coordinates of the point of the image.