It’s a manipulation of the coordinates.
They are shuffled, so that the total entries of the variable is not reduced (bijective) - but the shape of the two variables are not the same.
At the moment, this can be done by simple reassigning the variable’s entries (iteration).  In the backprop stage the inversion of this process is done for the activations and the gradients.
Is there any way of saving a computational graph of this process?