On 2D plane E values are displayed by the red color.
n values are displayed by the green color. This scrpt uses 1024×1024
float32 textures with the CLAMP_TO_EDGE boundary conditions.
It makes 2 it time steps per frame.
After relaxation transient this spiral is stable for M = 1.
Set M = 3 to watch influence of exitation wave alternation.
For M = 5 this instability leads to the spiral breakup.