createCanvas(400, 400);

}

​

function draw() {

  background(220);

  translate(width/2, height/2);

  const maxLayers = 6;

  const layers = constrain(map(mouseX, 0, width, 0, maxLayers), 0, maxLayers);

  drawCircle(width/2, layers);

}

​

function drawCircle(radius, layers) {

  circle(0, 0, radius * 2);

  if(layers > 0) {

    const NUM = 3;

    const ratio = 24/52;

    const ang = TAU / NUM;

    const rad = radius * (1-ratio);

    for(let i = 0; i < NUM; i ++) {

      const a = ang * i - PI/2;

      push();

      translate(cos(a) * rad, sin(a) * rad);

      drawCircle(radius * ratio, layers - 1);

      pop();

    }

  }

}