this.i = i;

  this.j = j;

  this.walls = [true, true, true, true];

  this.visited = false;

  this.highlighted = false;

​

  this.checkNeighbors = function() {

    var neighbors = [];

​

    var top = grid[index(i, j - 1)];

    var right = grid[index(i + 1, j)];

    var bottom = grid[index(i, j + 1)];

    var left = grid[index(i - 1, j)];

​

    if (top && !top.visited) {

      neighbors.push(top);

    }

    if (right && !right.visited) {

      neighbors.push(right);

    }

    if (bottom && !bottom.visited) {

      neighbors.push(bottom);

    }

    if (left && !left.visited) {

      neighbors.push(left);

    }

​

​

    if (neighbors.length > 0) {

      var r = floor(random(0, neighbors.length));

      return neighbors[r];

    } else {

      return undefined;

    }

  }

​

  this.highlight = function() {

    let x = this.i * w;

    let y = this.j * w;

    noStroke();

    noFill();

    rect(x, y, w, w);

    this.highlighted = true;

  }

​

  this.show = function() {

    let x = this.i * w;

    let y = this.j * w;

    noFill();

    stroke(255);

    if (this.walls[0]) {

      line(x, y, x + w, y);

    }

    if (this.walls[1]) {

      line(x + w, y, x + w, y + w);

    }

    if (this.walls[2]) {

      line(x + w, y + w, x, y + w);

    }

    if (this.walls[3]) {

      line(x, y + w, x, y);

    }

​

    if (this.visited) {

      noStroke();

      noFill();

      rect(x, y, w, w);

    }

    noFill();

    noStroke();

  }

}

​

function removeWalls(a, b) {

  var x = a.i - b.i;

  if (x === 1) {

    a.walls[3] = false;

    b.walls[1] = false;

  } else if (x === -1) {

    a.walls[1] = false;

    b.walls[3] = false;

  }

  var y = a.j - b.j;

  if (y === 1) {

    a.walls[0] = false;

    b.walls[2] = false;

  } else if (y === -1) {

    a.walls[2] = false;

    b.walls[0] = false;

  }

}