Before revision:  A typical approach is to represent the data elements at each time step in a compact one-dimensional form or via a one-dimensional ordering . Such 1D representations can then be placed in temporal order along a time line.
After revision:  A typical approach is to represent the data elements at each time step in a compact one-dimensional form or via a one-dimensional ordering ; visualizations of such orderings can then be placed in temporal order along a time line.