set.seed(829)
x = rnorm(3)
y = rnorm(3)
for (i in 1:150) {
  x = c(x, NA, rnorm(3, tail(x, 1)))
  y = c(y, NA, rnorm(3, tail(y, 1)))
}
x = c(x, NA)
y = c(y, NA)
xr = diff(range(x, na.rm = TRUE))
yr = diff(range(y, na.rm = TRUE))
x = c(x, x + xr, x + xr / 2, x + xr / 2)
y = c(y, y, y + yr, y - yr)
par(mar = rep(0, 4))
plot(x, y, type = "n", ann = FALSE, axes = FALSE)
polygon(x, y, col = sample(colors(), 151), border = NA)
