n = 1000 set.seed(3) tibble( i = 1:n, ran1 = c(arima.sim(list(ar=c(1.999, -0.9995)), n, sd=1e-3)), ran2 = c(arima.sim(list(ar=c(1.999, -0.9995)), n, sd=1e-3))) %>% mutate(theta = list(seq(0, 2*pi, len=200))) %>% unnest(cols=c(theta)) %>% rowwise() %>% mutate(dr = ran1 * cos(theta) + ran2 * cos(2*theta) + ran2 * sin(theta) + ran1 * sin(2*theta), r = .01 * (1 + i/n)^2 + (i/n)^2 * dr, x = r * cos(theta) + 10 * i/n, y = r * sin(theta) + ran1 * i/n) %>% ggplot() + geom_path(aes(x=x, y=y, group=i), lwd=.1) + theme_void()
