createCanvas(400, 400);

  rectMode(RADIUS)

  half = width/2

}

​

function squareCircle(radius) {

  sqWidth = sqrt(sq(radius)/2);

  return sqWidth;

}

​

function draw() {

  background(0);

  //red circle

  fill(255,0,0)

  redCirc = width;

  circle(half,half,redCirc)

  //green square

  fill(0,255,0)

  greenSqu = squareCircle(redCirc/2);

  rect(half,half,greenSqu,greenSqu)

  //blue circle

  fill(0,0,255)

  blueCirc = squareCircle(redCirc)

  circle(half,half,blueCirc)

  //yellow square

  fill(255,255,0)

  yellowSqu = squareCircle(blueCirc/2)

  rect(half,half,yellowSqu)

  //cyan circle

  fill(0,255,255)

  cyanCirc = squareCircle(blueCirc)

  circle(half,half,cyanCirc)

  //magenta square

  fill(255,0,255)

  magentaSqu = squareCircle(cyanCirc/2)

  rect(half,half,magentaSqu)

  //white circle

  fill(255,255,255)

  whiteCirc = squareCircle(cyanCirc)

  circle(half,half,whiteCirc)

  //grey square

  fill(128,128,128)

  greySqu = squareCircle(whiteCirc/2)

  rect(half,half,greySqu)

  //black circle

  fill(0,0,0)

  blackSqu = squareCircle(whiteCirc)

  circle(half,half,blackSqu)

}