maze = function(width, height, complexity, density) {
  shape = c((height / 2) * 2 + 1, (width / 2) * 2 + 1)
  complexity = (complexity * (5 * (shape[1] + shape[2])))
  density = (density * ((shape[1] / 2) * (shape[2] / 2)))
  Z = array(c(rep(0,shape[1]), rep(0,shape[2])), dim=c(shape[1], shape[2]))
  Z[1, ] = Z[shape[1], ] = 1
  Z[, 1] = Z[, shape[2]] = 1
  lappend <- function (lst, ...){
    lst <- c(lst, list(...))
    return(lst)
  }
  set.seed(1)
  for (i in 1:density){
    x = (round(runif(1, 1, shape[2]/2)))*2
    y = (round(runif(1, 1, shape[1]/2)))*2
    Z[y,x] = 1
    for (j in 1:complexity){
      neighbours = list()
      if (x > 2) { neighbours = lappend(neighbours, c(y, x-2)) }
      if (x < shape[2] - 2) { neighbours = lappend(neighbours, c(y, x+2)) }
      if (y > 2) { neighbours = lappend(neighbours, c(y-2, x)) }
      if (y < shape[1] - 2) { neighbours = lappend(neighbours, c(y+2, x)) }
      if (length(neighbours) > 1) {
        sample1 = round(runif(1, 1, length(neighbours)))
        y1 = neighbours[[sample1]][1]
        x1 = neighbours[[sample1]][2]
        if (Z[y1,x1] == 0) {
          Z[y1,x1] = 1
          Z[y1 + (y - y1)/2, x1 + (x - x1) / 2] = 1
          x = x1
          y = x1
        }
      }
    }
  }
}