const cellSize = 5;

const cells = []

​

const ON = 1;

const DYING = 0;

const OFF = -1;

​

const colors = {

  [ON]: "green",

  [DYING]: "tomato",

  [OFF]: "white"

}

​

​

function setup() {

  createCanvas(600, 600);

  noStroke()

​

  // Create the random Grid

  for (let j=0; j < width / cellSize; j++) {

    cells.push([])

    for (let k=0; k < height / cellSize; k++) {

      cells[j].push(OFF)

    }

  }

  // Seed random ON cells

  for (let i = 0; i < width /cellSize; i++) {

    for (let j = 0; j < height /cellSize / 10; j++) {

      cells[i][floor(random(width /cellSize))] = ON

    }

  }

  for (let i = 0; i < width /cellSize; i++) {

    for (let j = 0; j < height /cellSize; j++) {

      cells[i][floor(randomGaussian(0, width))] = ON

    }

  }  

}

​

​

function draw() {

  // background(255)

  for (let j = 0; j < width / cellSize; j++) {

    for (let k = 0; k < height / cellSize; k++) {

      const cell = cells[j][k];

      // If ON go to Dying

      if (cell === ON) {

        cells[j][k] = DYING  

      } // If Dying go to OFF

      else if (cell === DYING) {

        cells[j][k] = OFF

      } else {      

        // Turn ON if is OFF and has two ON neighbors

        // Dying does not count as ON

        const nw = (j > 0) && cells[j - 1][k - 1]

        const n  = cells[j][k -1]

        const ne = (j > 0) && cells[j - 1][k + 1]

        const w  = (j > 0) && cells[j - 1][k]

        const e  = (j + 1 < width /cellSize) && cells[j + 1][k]

        const sw = (j + 1 < width /cellSize) && cells[j + 1][k - 1];

        const s  = cells[j][k + 1];

        const se = (j + 1 < width /cellSize) && cells[j + 1][k + 1]

        if ([nw, n, ne, w, e, sw, s, se]

            .filter(v => v === ON).length === 2) {

            cells[j][k] = ON; 

        }

      }

      fill(colors[cells[j][k]])

      circle(j * cellSize, k * cellSize, cellSize)  

    }

  }

  // noLoop()

  // frameRate(1)

}