Folded “pulse stacks” from each of the observations used. The solid and dashed ellipses show the half power points of 2D Gaussians fitted to the data using a least squares method. The central observing frequency of each panel is indicated in the top left corner. The driftbands are repeated over 5 × P₃ so that the full drift pattern is visible at all frequencies. The pulse profile (grey line), and a simulated pulse profile (black line) from each 2D fit is shown in the panel above the corresponding pulse stack.