createCanvas(400, 400);

  background(0);

  rectMode(RADIUS)

  half = width / 2

  colours = [ 

              [255,0,0],

              [0,255,0],

              [0,0,255],

              [255,255,0],

              [0,255,255],

              [255,0,255],

              [255,255,255],

              [128,128,128],

              [0,0,0],

              [0,0,0]

            ];

}

​

function squareCircle(radius) {

  return sqrt(sq(radius) / 2);

}

​

function draw() {

  drawPair(width, 0)

}

​

function drawPair(circleDia, cycle) {

  fill(colours[cycle % 10]) // circle

  circle(half, half, circleDia)

  fill(colours[(cycle % 10) + 1]) // square

  rect(half, half, squareCircle(circleDia / 2))

  circleDia = squareCircle(circleDia)

  if (cycle < 8) {

    cycle = cycle + 2

    drawPair(circleDia, cycle)

  }

​

}