A simple clipping region

HTML

<div class="border">
  <div class="frame">
    <canvas id="c"></canvas>
  </div>
</div>

<div class="callback">
<p>The code for the frame is coming from <a href="https://generativeartistry.com" target="_blank">Generative Artistry</a></p>
</div>

SCSS

body {
  background: #fff;
  display: flex;
  height: 100vh;
  margin: 0;
  align-items: center;
  justify-content: center;
  position: relative;
  min-height: 560px;
  --blur: 2px;
}

.border {
  box-sizing: border-box;
  position: relative;
  background: black;
  background-image: -webkit-gradient(linear, right top, left bottom, from(#111), to(#000));
  padding: 20px;
  box-shadow: -1px 1px var(--blur) 1px rgba(0, 0, 0, 0.1), -2px 2px var(--blur) 1px rgba(0, 0, 0, 0.09), -3px 3px var(--blur) 1px rgba(0, 0, 0, 0.08), -4px 4px var(--blur) 1px rgba(0, 0, 0, 0.07), -5px 5px var(--blur) 1px rgba(0, 0, 0, 0.06), -6px 6px var(--blur) 1px rgba(0, 0, 0, 0.05), -7px 7px var(--blur) 1px rgba(0, 0, 0, 0.04), -8px 8px var(--blur) 1px rgba(0, 0, 0, 0.03), -9px 9px var(--blur) 1px rgba(0, 0, 0, 0.03), -10px 10px var(--blur) 1px rgba(0, 0, 0, 0.03), -11px 11px var(--blur) 1px rgba(0, 0, 0, 0.03), -12px 12px var(--blur) 1px rgba(0, 0, 0, 0.02), -13px 13px var(--blur) 1px rgba(0, 0, 0, 0.02), -14px 14px var(--blur) 1px rgba(0, 0, 0, 0.01), -15px 15px var(--blur) 1px rgba(0, 0, 0, 0.01), -16px 16px var(--blur) 1px rgba(0, 0, 0, 0.01);
}

.frame {
  left: 3%;
  top: 2.5%;
  box-shadow: inset -1px 1px 6px 1px rgba(0, 0, 0, 0.24);
  background: white;
  align-items: center;
  display: flex;
  padding: 40px;
  box-sizing: border-box;
}

canvas {
  box-shadow: inset 0 0 1px 0 rgba(0, 0, 0, 0.2);
  height: 320px;
  width: 320px;
  padding: 10px;
  background-size: cover;
  background-position: center center;
}
.callback {
  position: absolute;
  font-family: monospace;
  bottom: 10px;
}

JavaScript

const canvas = document.getElementById('c');
const ctx = canvas.getContext('2d');

const size = window.innerWidth;
const dpr = window.devicePixelRatio;
const s = size * dpr;

canvas.width = s;
canvas.height = s;
ctx.scale(dpr, dpr);

ctx.lineWidth = 8;
ctx.lineCap = 'round';

const center = s / 4;
const radius = s / 4;

const gap = 20;

const step = radius / gap;
const start = center - radius - (step / 2);
const end = center + radius + (step / 2);
const blockGap = s / 30;

/* Pythagorean theorem  */
const pyT = y => Math.sqrt(Math.pow(radius, 2) - Math.pow(y, 2))


let y, half;
const points = [];

for (let index = start; index <= end; index = index + step) {
  y = index;
  half = pyT(center - y);
  if (Number.isNaN(half)) {
    continue;
  }
  points.push({
    from: center - half + 10,
    to: center + half - 10,
    y
  })
}

const getRandomArbitrary = (max, min = 0) => Math.floor(Math.random() * (max - min + 1)) + min;


const splitToNums = (from, to) => {
  let n = to - from;
  const a = [];
  let s;
  while (n > 0) {
    s = getRandomArbitrary(n)
    a.push(s);
    n -= s;
  }
  return a;
}

const shuffle = a => {
  for (let i = a.length - 1; i > 0; i--) {
    const j = Math.floor(Math.random() * (i + 1));
    [a[i], a[j]] = [a[j], a[i]];
  }
  return a;
}

const limit = (v = []) => {
  const c = [];
  for (let index = 0; index < v.length; index++) {
    if (v[index] < blockGap) {
      if (index === 0) {
        c.push(v[index]);
      } else {
        c[0] = c[0] + v[index];
      }
    } else {
      c[c.length] = v[index]
    }

  }

  return c;
}


const splitToBlocks = p => {
  const {
    from,
    to,
    y
  } = p;
  const blox = shuffle(limit(splitToNums(from, to)));

  return {
    froms: [from, ...blox.map(v => Math.round(v + from))],
    tos: [...blox.map(v => {
      const s = Math.round(v + from - blockGap);
      return s < from ? from : s;
    }), to],
    y
  }
}

let blocks;
points.forEach((p, index) => {
  const {
    froms,
    tos,
   ...