Examples of participants’ traces (blue line) for different conditions and approximation of the plots by an ellipse (red dotted line). The angular position of the source is marked by a black circle. The center of the ellipse is marked by a red cross. These examples illustrate the diversity of plots in terms of angular error and reported width as well as the relevance of approximating plots with an ellipse. The example at the bottom right illustrates the limits of the approximation by an ellipse.