Compute pi digits with collisions p5.js

collision.js

let a = null;
let b = null;
let collisions = 0;
let digits = 6;
let steps = Math.pow(10, digits);

class Block {
  constructor(x, mass, velocity) {
    this.x = x;
    this.y = windowHeight*0.9;
    this.width = 100;
    this.height = -100;
    this.velocity = -velocity;
    this.mass = mass;
  }
  
  collide(block) {
    let bx1 = block.x;
    let bx2 = bx1 + block.width;
    
    let ax1 = this.x;
    let ax2 = ax1 + this.width;
    
    if(ax1 > bx1)
      return (bx2 >= ax1);
    return (ax2 >= bx1);
  }
  
  hitWall() {
    return (this.x <= 0);
  }
  
  updateCollision(block) {
    if(this.collide(block)) {
      collisions++;
      let v1 = (((this.mass-block.mass)/(block.mass+this.mass)) * this.velocity) + (2*block.mass*block.velocity)/(block.mass+this.mass);
      let v2 = (((block.mass-this.mass)/(block.mass+this.mass)) * block.velocity) + (2*this.mass*this.velocity)/(block.mass+this.mass);
      this.velocity = v1;
      block.velocity = v2;
    }
  }
  
  update() {
    if(this.hitWall()) {
      collisions++;
      this.velocity *= -1;
    }
    this.x += this.velocity;
  }
  
  draw() {
    rect(this.x, this.y, this.width, this.height);
  }
}

function setup() {
  createCanvas(windowWidth, windowHeight);
  a = new Block(windowWidth/2, Math.pow(steps,2), 1/steps);
  b = new Block(300, 1, 0);
  textSize(32); 
}

function draw() {
  background(39, 41, 48);
  text('Collisions: '+collisions, 10, 30);
  fill(107, 0, 4);
  rect(0, windowHeight*0.9, windowWidth, windowHeight*0.9);
  fill(82, 235, 255);
  for(i=0;i<steps;++i) {
    a.update();
    b.update();
    a.updateCollision(b);
  }
  a.draw();
  b.draw();
}

https://www.youtube.com/watch?v=m1Mmph4q6Pc