Simple class

Particle[] particles_a;
int nums = 300;
int noiseScale = 900;

void settings() {
  size(1920, 1080);
}


void setup(){
  frameRate(60);

  background(25, 8, 50);
  for(int i = 0; i < nums; ++i){
    particles_a[i] = new Particle(5.0, 6.0);
  }
}

class Particle {

  PVector dir;
  PVector vel;
  PVector pos;
  float speed;

  Particle (float x, float y) {

  dir = new PVector(0,0);
  vel = new PVector(0,0);
  pos = new PVector(x,y);
  speed = 0.5;
  }
}