let prevArray = [];

​

function setup() {

  // setup canvas

  createCanvas(400, 400);

  background(237, 183, 5);

​

  // drop shadow for particle trails

  drawingContext.shadowOffsetX = 2;

  drawingContext.shadowOffsetY = 2;

  drawingContext.shadowBlur = 10;

  drawingContext.shadowColor = "black";

​

  // particle settings

  ellipseMode(CENTER);

  fill("blue");

  blur(2);

  noStroke();

​

  // array to store particle data

  for (let i = 0; i < 20; i++) {

    let x = random(width);

    let y = random(height);

    let weight = int(random(1, 10));

    let angle = random(TWO_PI);

    let radius = random(1, 10);

    particleArray.push({ x, y, weight, angle, radius });

    prevArray.push({x, y})

  }

}

​

function draw() {

  for (let i = 0; i < particleArray.length; i++) {

    let { x, y, weight, angle, radius } = particleArray[i];

    ellipse(x, y, weight, weight);

    particleArray[i].x = x + radius * cos(angle);

    particleArray[i].y = y + radius * sin(angle);

    particleArray[i].angle += 0.02;

    particleArray[i].radius += 0.01;

    if (i != 0) {

      let { x: prevX, y: prevY } = prevArray[i - 1];

      let centerX = (x + prevX) / 2;

      let centerY = (y + prevY) / 2;

      let distance = dist(x, y, prevX, prevY);

      let startAngle = atan2(y - centerY, x - centerX);

      let endAngle = atan2(prevY - centerY, prevX - centerX);

      noFill();

      stroke("blue");

      strokeWeight(weight);

      arc(centerX, centerY, distance, distance, startAngle, endAngle);

    }

  }

}

​