Fig. 2

Computer-generated map, sampled from a monochromatic field. This figure shows an orientation map which we have drawn from a simulated invariant Gaussian random field with circular power spectrum. This figure was generated using a superposition of 30 plane waves with frequency vectors at the vertices of a random polygon inscribed in a circle, and random Gaussian weights (see the Appendix); what is plotted is the argument. In the unit of length displayed on the x- and y-axes, the wavelength is \(1/3\) here