outline

current_node_i = 0
current_node_j = 0
stack_i = [0]
stack_j = [0]
stack_ctr = 1
any_neighbors = 0
while (stack_ctr >= 0) {
  any_neighbors = 0
  if (current_node_i + 1 < HEIGHT && cells[i + 1, j].visited == false) any_neighbors |= 1
  if (current_node_j + 1 < WIDTH && cells[i, j+1].visited == false) any_neighbors |= 2
  if (current_node_i - 1 >= 0 && cells[i - 1, j].visited == false) any_neighbors |= 4
  if (current_node_j - 1 >= 0 && cells[i, j-1].visited == false) any_neighbors |= 8
  if (any_neighbors == 0) {
    current_node_i <= stack_i[stack_ctr - 1]
    current_node_j <= stack_j[stack_ctr - 1]
    stack_ctr <= stack_ctr - 1
  } else {
    n = random_neighbor(any_neighbors)
    stack_i[stack_ctr] <= current_node_i
    stack_j[stack_ctr] <= current_node_j
    stack_ctr <= stack_ctr + 1
    remove_walls()
    cells[current_node_i][current_node_j] |= visited;
    current_node_i <= n.i
    current_node_j <= n.j
  }