The New Journal of Physics has a paper describing how periodic forcing of oscillating systems form repeating patterns.

Wavenumber locking and pattern formation in spatially forced systems

http://www.iop.org/EJ/abstract/1367-2630/11/6/063016/?rss=2.0

Rotem Manor, Aric Hagberg, and Ehud Meron

This result matches empirical observations of experiment I made (Porcino, 1990) on how the ratio of the length of an insect's rear legs to its forelegs governs the wave patterns seen in their walking patterns. The rear legs provide the periodic forcing, and the locomotory neural network is the analogous oscillator system. The phase diagrams in their paper are very reminiscent of my experimental data charted in Figure 9 of (Porcino 1990). I am quite intrigued by the results of Manor et al., as I had been unable to derive a mathematical foundation for my results but they provide it very neatly.