The object X is reflected through the origin.
  That is, each point in X with coordinates
  \((x,y)\) is mapped to the position \((-x, -y)\).
This is equivalent to applying the affine transformation with matrix
  diag(c(-1,-1)). It is also equivalent to rotation about the origin
  by 180 degrees.
The command reflect is generic, with a method for
  pixel images and a default method.