I've been experimenting with the excellent GLGraphics library, in particular with particle systems, but I'm encountering what I think is an odd error. The screenshot below is taken directly from the unmodified ParticleSystem example that comes with the library. If you allow the particles to settle by leaving the mouse stationary some of the particles align themselves into straight lines and columns. I don't see anything in the GLSL shader or in the Processing sketch that would be directly responsible for this. What am I missing? Does anyone know what causes this and how it could be avoided?