let cellSize = 2;

// let ruleSet = [0, 0, 0, 1, 1, 1, 1, 0]

// let ruleSet = parseInt('000011010', 2);

let ruleSet = parseInt('000011110', 2);

​

let generation = 0;

​

function setup() {

  createCanvas(600, 600);

  cells = Array(floor(width / cellSize)).fill(0);

  cells[floor(cells.length / 2)] = 1;

}

​

function draw() {

  for (let i = 0; i < cells.length; i++) {

    if (cells[i] == 1) {

      fill(0);

    } else {

      fill(0, 0);

    }

    noStroke();

    rect(i * cellSize, generation * cellSize, cellSize, cellSize);

  }

  if (generation < height / cellSize) {

    let nextGen = Array(cells.length).fill(0);

    for (let i = 1; i < cells.length - 1; i++) {

      let left = cells[i - 1];

      let middle = cells[i];

      let right = cells[i + 1];

      nextGen[i] = rules(left, middle, right);

    }

    cells = nextGen;

    generation++;

  }

}

​

function rules(a, b, c) {

  let index = (a << 2) | (b << 1) | c;

  return (ruleSet >> index) & 1;

}

// // More clear code

// function rules(a, b, c) {

//   if (a == 1 && b == 1 && c == 1) return ruleSet[0];

//   if (a == 1 && b == 1 && c == 0) return ruleSet[1];

//   if (a == 1 && b == 0 && c == 1) return ruleSet[2];

//   if (a == 1 && b == 0 && c == 0) return ruleSet[3];

//   if (a == 0 && b == 1 && c == 1) return ruleSet[4];

//   if (a == 0 && b == 1 && c == 0) return ruleSet[5];

//   if (a == 0 && b == 0 && c == 1) return ruleSet[6];

//   // if (a == 0 && b == 0 && c == 0) return ruleSet[7];

//   return ruleSet[7]

// }

​

​

​