drunk <- function(n) {
  t <- 0:n
  p <- dbinom(t, n, 1/4)
  x <- 2*t-n
  plot(x, p)
  points(x[p==max(p)], p[p==max(p)], pch="X")
  Sys.sleep(0.2)
}
ignore <- sapply(0:60, drunk)