let canvas = 400

​

function setup() {

  createCanvas(canvas, canvas);

  x = width/2;

  y = height/2;

}

​

function draw() {

  background(220);

  rectMode(CENTER);

  noFill();

  /* ellipse(x,y,50,50);

  ellipse(x,y,100,100);

  ellipse(x,y,150,150);

  ellipse(x,y,180,180);

  ellipse(x,y,190,190); */

  // above code with for loop

  /* for(let dia = 30 ; dia<=canvas; dia += 10){

    //ellipse(x, y, dia, dia);

    strokeWeight(random(20));

    stroke(random(255), random(255), random(255));

    ellipse(x,y,dia,dia);

    }*/

  for(let i = 0;i<15;i++) { // want 6 circles (each diameter incremented by 6)

    let dia = 50 + i * 30;  // how many circles I want (circle size + circle number * diameter increase distance)

    ellipse(x,y,dia, dia);

  }

  noLoop();

}