https://bernhardfritz.github.io/p8g/editor/b92293cf8fbbbca032e0e20ce89b8377

sketch.js

import p8g, {
  background,
  createCanvas,
  line,
} from 'https://unpkg.com/p8g.js';

const p0 = [50, 50];
const p1 = [300, 100];
const p2 = [200, 300];

p8g.draw = () => {
  background(220);
  let bn_prev;
  for (let t = 0; t <= 1; t += 0.01) {
    const bn_x = (1 - t) * [(1 - t) * p0[0] + t * p1[0]] + t * [(1 - t) * p1[0] + t * p2[0]];
    const bn_y = (1 - t) * [(1 - t) * p0[1] + t * p1[1]] + t * [(1 - t) * p1[1] + t * p2[1]];
    const bn = [bn_x, bn_y];
    if (bn_prev) {
      line(bn_prev[0], bn_prev[1], bn[0], bn[1]);
    }
    bn_prev = bn;
  }
};

createCanvas(320, 320);