step by step

float x, y, prevX, prevY;
int dir;
color c;
color[] palette = {
  #BF245E,#EAB1AC,#291B36,#426175,#9DA9A3
};

void setup() {
  frameRate(20);
  size(500, 300);
  background(50);
  c = int(random(palette.length));
  fill(palette[c]);
  x = 0;
  y = random(height);
  prevX = x;
  prevY = y;
}

void draw() {
  float r = random(1);
  if (r > .5) {
    dir = 1;
  }
  else {
    dir = -1;
  }

  if (frameCount % 2 == 0) {
    x += random(20, 40);
  }
  else {
    x += random(10, 20);
    y += random(10, 30)*dir;
  }
  fill(palette[c]);
  stroke(240);
  line(prevX, prevY, x, y);
  ellipse(x, y, 8, 8);
  prevX = x;
  prevY = y;

  if (x > width || y > height || y < 0) {
    reset();
  }
}

void reset() {
  c = int(random(palette.length));
  fill(palette[c]);
  x = 0;
  prevX = x;
  y = random(50,height-50);
  prevY = y;
  filter(BLUR);
}