createCanvas(400, 400);

  rectMode(RADIUS)

  half = width/2

}

​

function squareCircle(radius) {

  sqWidth = sqrt(sq(radius)/2);

  return sqWidth;

}

​

function draw() {

  background(0);

  drawPair(width)

}

​

function drawPair() {

  fill(255,0,0) //red circle

  circle(half,half,width)

  fill(0,255,0) //green square

  rect(half,half,squareCircle(half))

  fill(0,0,255) //blue circle

  circle(half,half,squareCircle(width))

  fill(255,255,0) //yellow square

  rect(half,half,squareCircle(squareCircle(half)))

  fill(0,255,255) //cyan circle

  circle(half,half,squareCircle(squareCircle(width)))

  fill(255,0,255) //magenta square

  rect(half,half,squareCircle(squareCircle(squareCircle(half))))

  fill(255,255,255) //white circle

  circle(half,half,squareCircle(squareCircle(squareCircle(width))))

  fill(128,128,128) //grey square

  rect(half,half,squareCircle(squareCircle(squareCircle(squareCircle(half)))))

  fill(0,0,0) //black circle

  circle(half,half,squareCircle(squareCircle(squareCircle(squareCircle(width)))))

}