let i, len;

let reducedFractions = [];

​

function setup() {

  createCanvas(400, 400)

  frameRate(3)

  for (let n = 2; n < bound; n += 2) {

    for (let d = 1; d < 2; d++) {

      if (gcd(n, d) <= 1) {

        reducedFractions.push({ n:n, d:d })

      }

    }

  }

  i = 0

  len = reducedFractions.length

}

​

function draw() {

  translate(width/2, height/2)

​

  background(10)

  stroke(200, 200, 200)

  strokeWeight(4)

  let reducedFraction = reducedFractions[i % len]

  let numerator = reducedFraction.n

  let denominator = reducedFraction.d

  drawRose(0, 0, width*0.49, numerator, denominator, 0.0001)

  i++

}

​

function gcd(a, b) {

  if (b == 0) {

    return a

  }

  return gcd(b, a % b)

}

​

function drawRose(cx, cy, radius, numerator, denominator, ratio=0.001) {

  let k = numerator / denominator

  let x = [0, 0], 

      y = [0, 0];

  for (let i = 0; i < TWO_PI * denominator; i += TWO_PI * ratio) {

    let r = radius * cos(k*i)

    x[1] = cx + r * cos(i)

    y[1] = cy + r * sin(i)

    if (i > 0) {

      let dx = x[1] - cx,

          dy = y[1] - cy;

      push()

      colorMode(HSB)

      stroke(map(dx*dx + dy*dy, 0, radius*radius*0.85, 0, 255), 255, 230)

      line(x[0], y[0], x[1], y[1])

      pop()

    }

    x[0] = x[1]

    y[0] = y[1]

  }

}