Snapshot 1&2: Two examples of spiral patterns produced at phase shifts

.
Snapshot 3: Patterns that resemble plane waves at phase shift

.
The Kuramoto model describes a set of oscillators which are coupled sinuosoidally according to their phase differences.
In this demonstration, a 100x100 grid of oscillators is initialized with random phases

. Each oscillator is coupled to it's nearest neighbors within a variable radius

. The time evolution of the phases is governed by the differential equation

,
where the phase shift is

, and the sum goes over all oscillators at positions

for which

. The differential equation is solved for sufficient timesteps such that interesting patterns are observed, and the final phases of each oscillator displayed above.
For further details, see published work [1] on which this demonstration is based. For general information on the Kuramoto model, see the Wikipedia article of the same name.
[1] P.-J. Kim, et al. "Pattern Formation in a Two-Dimensional Array of Oscillators with Phase-Shifted Coupling,"
Phys. Rev. E.,
70(6): 065201, 2004.