let SIZE = 10;

let fr = 3;

let i,j,k,l,count,x,y;

let GRID, NEXT;

​

function setup() {

  frameRate(fr);

  createCanvas(windowWidth,windowHeight);

  COLS = floor(windowWidth / SIZE) + 2;

  ROWS = floor(windowHeight / SIZE) + 2;

//  COLS = 50; ROWS = 50;

//  print(COLS); print(ROWS);

​

  // Create GRIDS  

  GRID = new Array(COLS,ROWS);

  NEXT = GRID;

​

  // Fill with random noise

  for (i=0;i<COLS;i++){

    GRID[i] = new Array(10);

    for (j=0;j<ROWS;j++){

      GRID[i][j] = floor(random(2));     

    }

  }

  // Set outer ROWS / COLS to 0

  for (i=0;i<COLS;i++){

    GRID[i][0] = 0;      

    GRID[i][ROWS-1] = 0;      

  }

  for (j=0;j<ROWS;j++){

    GRID[0][j] = 0;      

    GRID[COLS-1][j] = 0;      

  }

}

​

function draw() {

  // Count surroundings of each cell

  for (i=1;i<COLS-1;i++){

    for (j=1;j<ROWS-1;j++){

      count = 0;

      for (k=i-1;k<i+2;k++){

        for (l=j-1;l<j+2;l++){

          count += GRID[k][l];

        }

      }

      count -= GRID[i][j];

      // print(count);

      // evaluate

      if (GRID[i][j] == 0 && count == 3) {

        NEXT[i][j] = 1; 

      } else if (GRID[i][j] == 1 && count == 2){

        NEXT[i][j] = 1; 

      } else if (GRID[i][j] == 1 && count == 3){

        NEXT[i][j] = 1; 

      } else { 

        NEXT[i][j] = 0;

      }

    }

  }  

​

  // Display all except borders

  for (i=1;i<COLS;i++){

    for (j=1;j<ROWS;j++){

      x = i * SIZE;

      y = j * SIZE;

      fill (NEXT[i][j] * -255 + 255);

      stroke (NEXT[i][j] * -255 + 255);  

      square(x,y,SIZE - 2, SIZE / 2)      

    }

  }  

  // Prepair next cycle

  GRID = NEXT;  

}